fix(ui-color-picker): complete color mixer button alignment fix

Remove static alignSelf from colorMixerButtonContainer to allow dynamic
alignment control via inline styles. This prevents visual jump on load
by letting the button start at flex-end and transition to flex-start
after labelHeight calculation completes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: balzss

packages/ui-color-picker/src/ColorPicker/styles.ts

@@ -122,7 +122,6 @@ const generateStyle = (
     },
     colorMixerButtonContainer: {
       label: 'colorPicker__colorMixerButtonContainer',
-      alignSelf: 'flex-start',
       marginInlineStart: componentTheme.colorMixerButtonContainerLeftMargin
     },
     popoverContentContainer: {