Add Android Tablet system image on Android 15.

Also reorder the yaml a bit, by the API level.

Bug: 391893869
Change-Id: I4df41fe2320606324483a7219ef09112447bd2bc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6191113
Reviewed-by: Erik Staab <estaab@chromium.org>
Reviewed-by: Renuga Nanjappan <rnanjappan@chromium.org>
Auto-Submit: Haiyang Pan <hypan@google.com>
Commit-Queue: Haiyang Pan <hypan@google.com>
Cr-Commit-Position: refs/heads/main@{#1410499}
NOKEYCHECK=True
GitOrigin-RevId: bef1d0f2d8c0485ad38842b01a4a4682c6a8f5d0