Clean-up of task move request bounds adjustment stubs in Core

Following discussion in
https://googleplex-android-review.git.corp.google.com/c/platform/frameworks/base/+/33630551/comment/cb2c799d_65ae570d/,
there does not seem to be any valid case in which bounds should be
adjusted by Core.

Bug: 400407139
Fix: 421882376
Flag: com.android.window.flags.enable_window_repositioning_api
Test: N/A
Change-Id: Ida2683ca9ad77d70cf22135fdc385b4f0adf1719