[Flaky test] `xmodule/partitions/tests/test_partitions.py::TestPartitionService::test_get_user_group_id_for_partition`

This test fails intermittently and has been deleted according to the Flaky Test Process in https://github.com/openedx/edx-platform/pull/35545.

See docs on how to address flaky tests for why this should be fixed and how to go about it.

• Failing CI run: https://github.com/openedx/edx-platform/actions/runs/11038973818/job/30663409464
• Subsequent Passing CI run: https://github.com/openedx/edx-platform/actions/runs/11038973818/job/30667857626

Related: https://github.com/openedx/edx-platform/issues/35641

__________ TestPartitionService.test_get_user_group_id_for_partition ___________

self = <xmodule.partitions.tests.test_partitions.TestPartitionService testMethod=test_get_user_group_id_for_partition>

    def test_get_user_group_id_for_partition(self):
        # assign the first group to be returned
        user_partition_id = self.user_partition.id
        groups = self.user_partition.groups
        self.user_partition.scheme.current_group = groups[0]
    
        # get a group assigned to the user
        group1_id = self.partition_service.get_user_group_id_for_partition(self.user, user_partition_id)
>       assert group1_id == groups[0].id
E       AssertionError: assert 1 == 0
E        +  where 0 = Group(id=0, name='Group 1').id

xmodule/partitions/tests/test_partitions.py:473: AssertionError

(Previously filed as https://2u-internal.atlassian.net/browse/CR-7071)

Start with xmodule/partitions/tests/test_partitions.py::TestPartitionService::test_get_user_group_id_for_partition and compare the failing and subsequent passing CI runs linked in the issue. Follow the Flaky Test Process guidance to identify why the expected group ID intermittently differs, then restore the test after addressing the cause and verify it passes consistently.