[SPARK-27871][SQL][FOLLOW-UP] Format config name to follow the other …

…boolean conf naming convention

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

Change config name from `spark.sql.optimizer.reassignLambdaVariableID` to `spark.sql.optimizer.reassignLambdaVariableID.enabled`.

### Why are the changes needed?

To follow the other boolean conf naming convention.

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

No, it's newly added in Spark 3.0.

### How was this patch tested?

Pass Jenkins.

Closes #27063 from Ngone51/SPARK-27871-FOLLOWUP.

Authored-by: yi.wu <yi.wu@databricks.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>

sql/catalyst/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala

@@ -234,7 +234,7 @@ object SQLConf {
     .createOptional
 
   val OPTIMIZER_REASSIGN_LAMBDA_VARIABLE_ID =
-    buildConf("spark.sql.optimizer.reassignLambdaVariableID")
+    buildConf("spark.sql.optimizer.reassignLambdaVariableID.enabled")
       .doc("When true, Spark optimizer reassigns per-query unique IDs to LambdaVariable, so that " +
         "it's more likely to hit codegen cache.")
     .booleanConf