Correct thumbnail clipping in landscape 10% split

Addresses an issue where thumbnails were incorrectly clipped in landscape split-screen, particularly with 10% ratios. This occurred due to miscalculated post-rotation translation, leading to content being drawn out of bounds.

Key changes:
- Consistent Rotation: Thumbnails are now always rotated when in split-screen configuration.
- Dynamic Translation Adjustment: Introduces a specific translation adjustment for `postTranslate.dy` that accounts for clipping in horizontal split-screen scenarios. This adjustment utilizes the `splitThumbnailClipHint` to precisely position the thumbnail.

The adjustment applies under the following conditions to mitigate regression risk:
- Split screen mode is active.
- Applications are horizontally stacked (`!appsStackedVertically`).
- Device is rotated 90 degrees and split is 10% on the left (`SNAP_TO_2_10_90`, `SPLIT_POSITION_TOP_OR_LEFT`).
- OR device is rotated 270 degrees and split is 10% on the right (`SNAP_TO_2_90_10`, `SPLIT_POSITION_BOTTOM_OR_RIGHT`).

Bug: 426438170
Flag: com.android.wm.shell.enable_flexible_two_app_split
Video: After: http://recall/-/gvQq7Z7JECwxnxKrBmr3wt/OuOFKIm7Rr54b7cCj8kXU
Test: Manual
Change-Id: I80ab2df3cde5a6a57cff3824d8fa9bb7546dec2e