Import "TraitFactory" from "traits.api"

[rahulporuri]

This PR makes a very trivial/simple change - it imports TraitFactory from traits.api instead of traits.trait_factory. This was fixed in traits in enthought/traits#730 and has been available in traits since v 6.0.0.

[aaronayres35]

LGTM

[rahulporuri]

I think we have seen this failure before. Restarted CI job because AFAIK this is an intermittent failure.

======================================================================
FAIL: test_qt_process_events_process_all (traitsui.testing.tests.test_gui.TestProcessEventsRepeated)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\a\traitsui\traitsui\.edm\envs\traitsui-test-3.6-pyqt\lib\site-packages\traitsui\testing\tests\test_gui.py", line 154, in test_qt_process_events_process_all
    self.assertEqual(n_left_behind_events, 0, msg)
AssertionError: 8 != 0 : Expected 10 events processed on the objects and zero events left on the queue after running process_cascade_events. Found 2 processed with 8 left behind.

[aaronayres35]

xref: #951