Revert "Fix post commit xlang jdbcio test failure (apache#35428)"

This reverts commit 6ac5009.

Author: shunping

.github/trigger_files/beam_PostCommit_Python.json

@@ -1,5 +1,5 @@
 {
   "comment": "Modify this file in a trivial way to cause this test suite to run.",
-  "modification": 2
+  "modification": 3
 }
 

.github/trigger_files/beam_PostCommit_Python_Xlang_Gcp_Direct.json

@@ -1,4 +1,4 @@
 {
   "comment": "Modify this file in a trivial way to cause this test suite to run",
-  "modification": 7
+  "modification": 9
 }

sdks/python/apache_beam/io/external/xlang_jdbcio_it_test.py

@@ -36,8 +36,6 @@
 from apache_beam.testing.test_pipeline import TestPipeline
 from apache_beam.testing.util import assert_that
 from apache_beam.testing.util import equal_to
-from apache_beam.typehints.schemas import LogicalType
-from apache_beam.typehints.schemas import MillisInstant
 from apache_beam.utils.timestamp import Timestamp
 
 # pylint: disable=wrong-import-order, wrong-import-position, ungrouped-imports
@@ -241,10 +239,6 @@ def test_xlang_jdbc_write_read(self, database):
 
     config = self.jdbc_configs[database]
 
-    # Register MillisInstant logical type to override the mapping from Timestamp
-    # originally handled by MicrosInstant.
-    LogicalType.register_logical_type(MillisInstant)
-
     with TestPipeline() as p:
       p.not_use_test_runner_api = True
       _ = (
@@ -355,10 +349,6 @@ def custom_row_equals(expected, actual):
               classpath=config['classpath'],
           ))
 
-    # Register MillisInstant logical type to override the mapping from Timestamp
-    # originally handled by MicrosInstant.
-    LogicalType.register_logical_type(MillisInstant)
-
     # Run read pipeline with custom schema
     with TestPipeline() as p:
       p.not_use_test_runner_api = True