Support for Windows home/end keyboard shortcuts

Adds floatingLabelAlignment to position the label above the field.

* Added the new Material 3 colors to ColorScheme.

* Deprecated primaryVariant and secondaryVariant colors in the ColorScheme.

* Added a flutter fix for the deprecated colors.

Fixing a calculation when jumping to an offset with a large caret as compared to the viewport.

See https://github.com/flutter/flutter/issues/93975

This reverts commit 9103b373.