Don't crop task with RemoteAnimaionTarget#contentInsets

..when willShowImeOnTarget is true, in case the task surface cropped by
the task bar insets since the task bar will end up stashed by IME
visible.

Bug: 219981732
Test: manual as steps
 0) enable taskbar with Settings > Developer options > Smallest width
    as 600dp.
 1) launch an app from all apps and show the IME by tapping the
    editor.
 2) swipe out to home and launch it again by pressing the shortcut.
 3) Verify the animating task preview with IME shown without being
    cropped.

Change-Id: I8d802887bd382a7d6f6429e269501c924e81c51b