python test_timeline test_auto_transition fails often on CI

Disabling this test on the CI since it seems to fail fairly often:

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FAIL: test_auto_transition (python.test_timeline.TestTransitions)
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Traceback (most recent call last):
  File "/builds/tpm/gst-plugins-base/gst-build/subprojects/gst-editing-services/tests/check/python/test_timeline.py", line 287, in test_auto_transition
    self.assertTrue(layers[0].props.auto_transition)
AssertionError: False is not true