Fixes #129590

* Consider `AxisDirection` when calculating scroll offset used in determining TextSelection during a drag/long press drag. Previously it seems that we were assuming the direction was always vertical https://github.com/flutter/flutter/blob/30cc83198544582b858e48c7bb9d761ecdb3d944/packages/flutter/lib/src/widgets/text_selection.dart#L2842-L2844 .
* SelectableText now considers RenderEditable offset changes and Scrollable offset changes when calculating the TextSelection during a long press drag.