[HOT-FIX] Fix the SQLBase.g4

### What changes were proposed in this pull request?
Remove the duplicate code

See the build failure: https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Compile/job/spark-master-compile-maven-hadoop-3.2/986/

### Why are the changes needed?
Fix the compilation

### Does this PR introduce any user-facing change?
No

### How was this patch tested?
The existing tests

Closes #26445 from gatorsmile/hotfixPraser.

Authored-by: Xiao Li <gatorsmile@gmail.com>
Signed-off-by: Xiao Li <gatorsmile@gmail.com>

sql/catalyst/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBase.g4

@@ -669,10 +669,6 @@ multipartIdentifier
     : parts+=errorCapturingIdentifier ('.' parts+=errorCapturingIdentifier)*
     ;
 
-multipartIdentifierList
-    : multipartIdentifier (',' multipartIdentifier)*
-    ;
-
 tableIdentifier
     : (db=errorCapturingIdentifier '.')? table=errorCapturingIdentifier
     ;