[SPARK-29796][SQL][TESTS] HiveExternalCatalogVersionsSuite should ignore preview release

### What changes were proposed in this pull request?

This aims to exclude the `preview` release to recover `HiveExternalCatalogVersionsSuite`. Currently, new preview release breaks `branch-2.4` PRBuilder since yesterday. New release (especially `preview`) should not affect `branch-2.4`.
- #26417 (Failed 4 times)

### Why are the changes needed?

**BEFORE**
```scala
scala> scala.io.Source.fromURL("https://dist.apache.org/repos/dist/release/spark/").mkString.split("\n").filter(_.contains("""<li><a href="spark-""")).map("""<a href="spark-(\d.\d.\d)/">""".r.findFirstMatchIn(_).get.group(1))
java.util.NoSuchElementException: None.get
```

**AFTER**
```scala
scala> scala.io.Source.fromURL("https://dist.apache.org/repos/dist/release/spark/").mkString.split("\n").filter(_.contains("""<li><a href="spark-""")).filterNot(_.contains("preview")).map("""<a href="spark-(\d.\d.\d)/">""".r.findFirstMatchIn(_).get.group(1))
res5: Array[String] = Array(2.3.4, 2.4.4)
```

### Does this PR introduce any user-facing change?

No.

### How was this patch tested?

This should pass the PRBuilder.

Closes #26428 from dongjoon-hyun/SPARK-HiveExternalCatalogVersionsSuite.

Authored-by: Dongjoon Hyun <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: dongjoon-hyun

sql/hive/src/test/scala/org/apache/spark/sql/hive/HiveExternalCatalogVersionsSuite.scala

@@ -237,6 +237,7 @@ object PROCESS_TABLES extends QueryTest with SQLTestUtils {
       Source.fromURL(s"${releaseMirror}/spark").mkString
         .split("\n")
         .filter(_.contains("""<li><a href="spark-"""))
+        .filterNot(_.contains("preview"))
         .map("""<a href="spark-(\d.\d.\d)/">""".r.findFirstMatchIn(_).get.group(1))
         .filter(_ < org.apache.spark.SPARK_VERSION)
     } catch {