[wm]: Freeform window layout while SIP showing

1. Set the input method target to all windows of the AppWindowToken
which the input method target window belongs, when input method
target is in freeform windowing mode.

2. If the freeform window has a dim, then apply an offset to dimBounds.

Test: atest WindowFrameTests#testFreeformContentInsets
Test: Run the test app (ex. PopupWithInput) > Launch to freeform mode
> Move the app near the location of IME

Bug: 123693028
Change-Id: Ib11d3ee05dd26ee1f28f12895ae300af7f3d0da7
(cherry picked from commit 4cbf77f88c3d7e323bcb6edd7aec1aa4ce58cd79)