Changes Roll-up

[robloo]

• Make ColorPicker button content customizable
  • Port of upstream Make ColorPicker button content customizable.  AvaloniaUI/Avalonia#13073
• Deferred scrolling
  • Port of upstream Deferred scrolling AvaloniaUI/Avalonia#13644
• Allow ColorPicker-Flyout to swap position if needed
  • Port of upstream Fix: Allow ColorPicker-Fylout to swap position if needed AvaloniaUI/Avalonia#13567
• Fix expander chevron flip when collapsing or expanding is canceled
  • This is based on, but not a direct port of, fix: Expander header icon flip when collapsing or expanding canceled AvaloniaUI/Avalonia#13780
  • The existing FA control theme for expander had to be heavily modified in some areas to stop using the ToggleButton.Tag property for the glyph. This resulted in some simplifications overall (re-use header ToggleButton theme) and the control theme now aligns more closely to upstream.
  • Added Expander expanding/collapsing disabled examples (which can be revered if desired)

Closes #517