Fix roslyn analyzer issues

```
/__w/1/s/src/libraries/Common/src/System/Data/Common/MultipartIdentifier.cs(71,17): error CA2249: Use 'string.Contains' instead of 'string.IndexOf' to improve readability (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2249) [/__w/1/s/src/libraries/System.Data.Common/src/System.Data.Common.csproj]
/__w/1/s/src/libraries/Common/src/System/Data/Common/MultipartIdentifier.cs(71,55): error CA2249: Use 'string.Contains' instead of 'string.IndexOf' to improve readability (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2249) [/__w/1/s/src/libraries/System.Data.Common/src/System.Data.Common.csproj]
/__w/1/s/src/libraries/Common/src/System/Data/Common/MultipartIdentifier.cs(114,33): error CA2249: Use 'string.Contains' instead of 'string.IndexOf' to improve readability (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2249) [/__w/1/s/src/libraries/System.Data.Common/src/System.Data.Common.csproj]
/__w/1/s/src/libraries/Common/src/System/Data/Common/MultipartIdentifier.cs(136,33): error CA2249: Use 'string.Contains' instead of 'string.IndexOf' to improve readability (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2249) [/__w/1/s/src/libraries/System.Data.Common/src/System.Data.Common.csproj]
/__w/1/s/src/libraries/Common/src/System/Data/Common/MultipartIdentifier.cs(141,33): error CA2249: Use 'string.Contains' instead of 'string.IndexOf' to improve readability (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2249) [/__w/1/s/src/libraries/System.Data.Common/src/System.Data.Common.csproj]
/__w/1/s/src/libraries/System.Data.Common/src/System/Data/Common/DBCommandBuilder.cs(736,56): error CA2249: Use 'string.Contains' instead of 'string.IndexOf' to improve readability (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2249) [/__w/1/s/src/libraries/System.Data.Common/src/System.Data.Common.csproj]
/__w/1/s/src/libraries/System.Data.Common/src/System/Data/Common/DBCommandBuilder.cs(740,56): error CA2249: Use 'string.Contains' instead of 'string.IndexOf' to improve readability (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2249) [/__w/1/s/src/libraries/System.Data.Common/src/System.Data.Common.csproj]
```

Remaining:
`/__w/1/s/src/libraries/System.Data.Common/src/System/Data/Common/DbConnectionOptions.cs(168,26): error CA1862: Prefer using 'string.Equals(string, StringComparison)' to perform a case-insensitive comparison (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1862) [/__w/1/s/src/libraries/System.Data.Common/src/System.Data.Common.csproj]`

Author: radical

src/libraries/Common/src/System/Data/Common/MultipartIdentifier.cs

@@ -68,7 +68,7 @@ private static bool IsWhitespace(char ch)
                 throw ADP.InvalidMultipartNameToManyParts(property, name, limit);
             }
 
-            if (-1 != leftQuote.IndexOf(separator) || -1 != rightQuote.IndexOf(separator) || leftQuote.Length != rightQuote.Length)
+            if (leftQuote.Contains(separator) || rightQuote.Contains(separator) || leftQuote.Length != rightQuote.Length)
             {
                 throw ADP.InvalidMultipartNameIncorrectUsageOfQuotes(property, name);
             }
@@ -111,7 +111,7 @@ private static bool IsWhitespace(char ch)
                                 state = MPIState.MPI_ParseQuote;
                             }
                             else
-                            if (-1 != rightQuote.IndexOf(testchar))
+                            if (rightQuote.Contains(testchar))
                             { // If we shouldn't see a right quote
                                 throw ADP.InvalidMultipartNameIncorrectUsageOfQuotes(property, name);
                             }
@@ -133,12 +133,12 @@ private static bool IsWhitespace(char ch)
                                 state = MPIState.MPI_Value;
                             }
                             else // Quotes are not valid inside a non-quoted name
-                            if (-1 != rightQuote.IndexOf(testchar))
+                            if (rightQuote.Contains(testchar))
                             {
                                 throw ADP.InvalidMultipartNameIncorrectUsageOfQuotes(property, name);
                             }
                             else
-                            if (-1 != leftQuote.IndexOf(testchar))
+                            if (leftQuote.Contains(testchar))
                             {
                                 throw ADP.InvalidMultipartNameIncorrectUsageOfQuotes(property, name);
                             }

src/libraries/System.Data.Common/src/System/Data/Common/DBCommandBuilder.cs

@@ -733,11 +733,11 @@ private void BuildInformation(DataTable schemaTable)
             string quotePrefix = QuotePrefix;
             string quoteSuffix = QuoteSuffix;
 
-            if (!string.IsNullOrEmpty(quotePrefix) && (-1 != baseTableName.IndexOf(quotePrefix, StringComparison.Ordinal)))
+            if (!string.IsNullOrEmpty(quotePrefix) && baseTableName.Contains(quotePrefix, StringComparison.Ordinal))
             {
                 throw ADP.DynamicSQLNestedQuote(baseTableName, quotePrefix);
             }
-            if (!string.IsNullOrEmpty(quoteSuffix) && (-1 != baseTableName.IndexOf(quoteSuffix, StringComparison.Ordinal)))
+            if (!string.IsNullOrEmpty(quoteSuffix) && baseTableName.Contains(quoteSuffix, StringComparison.Ordinal))
             {
                 throw ADP.DynamicSQLNestedQuote(baseTableName, quoteSuffix);
             }