fix the import of pyface.ui.qt.color for the new update

[homosapien-lcy]

The new pyface update move the qt tool kit from pyface.ui.qt4 to the pyface.ui.qt, this PR fixes the examples broken due to this update, closes #1024

[homosapien-lcy]

One of the test failed (EDM, macos-latest, pyside6, python3.8):

ImportError: Failed to import test module: enable.savage.svg.backends.kiva.tests.test_renderer
Traceback (most recent call last):
  File "/Users/runner/work/enable/enable/.edm/envs/enable-test-3.8-pyside6/lib/python3.8/unittest/loader.py", line 436, in _find_test_path
    module = self._get_module_from_name(name)
  File "/Users/runner/work/enable/enable/.edm/envs/enable-test-3.8-pyside6/lib/python3.8/unittest/loader.py", line 377, in _get_module_from_name
    __import__(name)
  File "/Users/runner/work/enable/enable/.edm/envs/enable-test-3.8-pyside6/lib/python3.8/site-packages/enable/savage/svg/backends/kiva/tests/test_renderer.py", line 12, in <module>
    from enable.savage.svg.backends.kiva.renderer import (
  File "/Users/runner/work/enable/enable/.edm/envs/enable-test-3.8-pyside6/lib/python3.8/site-packages/enable/savage/svg/backends/kiva/renderer.py", line 14, in <module>
    import numpy as np
  File "/Users/runner/work/enable/enable/.edm/envs/enable-test-3.8-pyside6/lib/python3.8/site-packages/numpy/__init__.py", line 140, in <module>
    from . import core
  File "/Users/runner/work/enable/enable/.edm/envs/enable-test-3.8-pyside6/lib/python3.8/site-packages/numpy/core/__init__.py", line 23, in <module>
    from . import multiarray
  File "/Users/runner/work/enable/enable/.edm/envs/enable-test-3.8-pyside6/lib/python3.8/site-packages/numpy/core/multiarray.py", line 10, in <module>
    from . import overrides
  File "/Users/runner/work/enable/enable/.edm/envs/enable-test-3.8-pyside6/lib/python3.8/site-packages/numpy/core/overrides.py", line 6, in <module>
    from numpy.core._multiarray_umath import (
RuntimeError: NumPy was built with baseline optimizations: 
(SSE SSE2 SSE3 SSSE3 SSE41 POPCNT SSE42 AVX F16C AVX2) but your machine doesn't support:
(AVX2).

seems to be a unique problem to macos machine for pyside6?

[dpinte]

The issue you report with numpy is a known issue with numpy in Github Action workers.