Add permission for self window management

This permission will be granted only by the default browser role for
security reasons as we didn't want to expose such extensive window
management capabilities to all apps and it's the browser team who asked
for this feature as there is a Web API for moving windows.

go/android-public-window-repositioning-api

Bug: 407607317
Bug: 400407139
Flag: com.android.window.flags.enable_window_repositioning_api
Test: N/A
Change-Id: I6b41512f2a15c3af44a9d546437e23d8ad62e660