Change Configuration.Json to use a regular Dictionary. (#50611)

The other Configuration providers use a regular Dictionary.

This allows for SortedDictionary to be trimmed in a default Blazor WASM app, saving roughly 4 KB .br compresse.

Author: eerhardt

src/libraries/Microsoft.Extensions.Configuration.Json/src/JsonConfigurationFileParser.cs

@@ -13,7 +13,7 @@ internal sealed class JsonConfigurationFileParser
     {
         private JsonConfigurationFileParser() { }
 
-        private readonly SortedDictionary<string, string> _data = new SortedDictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+        private readonly Dictionary<string, string> _data = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
         private readonly Stack<string> _paths = new Stack<string>();
 
         public static IDictionary<string, string> Parse(Stream input)