Use helper GetPickerWidget() function in wxFontPickerCtrl.

No real changes, just use a helper function instead of an ugly M_PICKER macro.

See #11614.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76159 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Add font colour support to wxFontPickerCtrl.

Currently this is only really implemented under Windows, just as the colour
support in wxFontDialog, but make the API available under all platforms for
consistency.

Closes #11614.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76160 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775