[SPARK-46227][SQL] Move withSQLConf from SQLHelper to SQLConfHelper

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

This pr moves method `withSQLConf` from `SQLHelper` in catalyst test module to `SQLConfHelper` trait in catalyst module. To make it easy to use such case: `val x = withSQLConf {}`, this pr also changes its return type.

### Why are the changes needed?

A part of apache#44013

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

no

### How was this patch tested?

Pass CI

### Was this patch authored or co-authored using generative AI tooling?

no

Closes apache#44142 from ulysses-you/withSQLConf.

Authored-by: ulysses-you <ulyssesyou18@gmail.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>

Author: ulysses-you

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SQLConfHelper.scala

@@ -17,6 +17,7 @@
 
 package org.apache.spark.sql.catalyst
 
+import org.apache.spark.sql.AnalysisException
 import org.apache.spark.sql.internal.SQLConf
 
 /**
@@ -29,4 +30,32 @@ trait SQLConfHelper {
    * See [[SQLConf.get]] for more information.
    */
   def conf: SQLConf = SQLConf.get
+
+  /**
+   * Sets all SQL configurations specified in `pairs`, calls `f`, and then restores all SQL
+   * configurations.
+   */
+  protected def withSQLConf[T](pairs: (String, String)*)(f: => T): T = {
+    val conf = SQLConf.get
+    val (keys, values) = pairs.unzip
+    val currentValues = keys.map { key =>
+      if (conf.contains(key)) {
+        Some(conf.getConfString(key))
+      } else {
+        None
+      }
+    }
+    keys.lazyZip(values).foreach { (k, v) =>
+      if (SQLConf.isStaticConfigKey(k)) {
+        throw new AnalysisException(s"Cannot modify the value of a static config: $k")
+      }
+      conf.setConfString(k, v)
+    }
+    try f finally {
+      keys.zip(currentValues).foreach {
+        case (key, Some(value)) => conf.setConfString(key, value)
+        case (key, None) => conf.unsetConf(key)
+      }
+    }
+  }
 }

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/plans/SQLHelper.scala

@@ -23,41 +23,13 @@ import scala.util.control.NonFatal
 
 import org.scalatest.Assertions.fail
 
-import org.apache.spark.sql.AnalysisException
+import org.apache.spark.sql.catalyst.SQLConfHelper
 import org.apache.spark.sql.catalyst.util.DateTimeTestUtils
 import org.apache.spark.sql.catalyst.util.DateTimeUtils.getZoneId
 import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.util.Utils
 
-trait SQLHelper {
-
-  /**
-   * Sets all SQL configurations specified in `pairs`, calls `f`, and then restores all SQL
-   * configurations.
-   */
-  protected def withSQLConf(pairs: (String, String)*)(f: => Unit): Unit = {
-    val conf = SQLConf.get
-    val (keys, values) = pairs.unzip
-    val currentValues = keys.map { key =>
-      if (conf.contains(key)) {
-        Some(conf.getConfString(key))
-      } else {
-        None
-      }
-    }
-    keys.lazyZip(values).foreach { (k, v) =>
-      if (SQLConf.isStaticConfigKey(k)) {
-        throw new AnalysisException(s"Cannot modify the value of a static config: $k")
-      }
-      conf.setConfString(k, v)
-    }
-    try f finally {
-      keys.zip(currentValues).foreach {
-        case (key, Some(value)) => conf.setConfString(key, value)
-        case (key, None) => conf.unsetConf(key)
-      }
-    }
-  }
+trait SQLHelper extends SQLConfHelper {
 
   /**
    * Generates a temporary path without creating the actual file/directory, then pass it to `f`. If

sql/core/src/test/scala/org/apache/spark/sql/internal/ExecutorSideSQLConfSuite.scala

@@ -58,7 +58,7 @@ class ExecutorSideSQLConfSuite extends SparkFunSuite with SQLTestUtils {
     }
   }
 
-  override def withSQLConf(pairs: (String, String)*)(f: => Unit): Unit = {
+  override def withSQLConf[T](pairs: (String, String)*)(f: => T): T = {
     pairs.foreach { case (k, v) =>
       SQLConf.get.setConfString(k, v)
     }

sql/core/src/test/scala/org/apache/spark/sql/test/SQLTestUtils.scala

@@ -243,7 +243,7 @@ private[sql] trait SQLTestUtilsBase
     protected override def _sqlContext: SQLContext = self.spark.sqlContext
   }
 
-  protected override def withSQLConf(pairs: (String, String)*)(f: => Unit): Unit = {
+  protected override def withSQLConf[T](pairs: (String, String)*)(f: => T): T = {
     SparkSession.setActiveSession(spark)
     super.withSQLConf(pairs: _*)(f)
   }

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveSerDeSuite.scala

@@ -84,7 +84,7 @@ class HiveSerDeSuite extends HiveComparisonTest with PlanTest with BeforeAndAfte
   }
 
   // Make sure we set the config values to TestHive.conf.
-  override def withSQLConf(pairs: (String, String)*)(f: => Unit): Unit =
+  override def withSQLConf[T](pairs: (String, String)*)(f: => T): T =
     SQLConf.withExistingConf(TestHive.conf)(super.withSQLConf(pairs: _*)(f))
 
   test("Test the default fileformat for Hive-serde tables") {