Prevent duplicate config change in ComposeView

Only dispatch the config change to the children view if something has
actually changed. This helps because FrameLayoutTouchPassthrough may be
getting duplicate config changes (one from the view hierarchy and one
from FragmentHostManager).

Test: manual, perform config changes.
Fixes: 434389035
Flag: EXEMPT bugfix
Change-Id: If9c46d131e9af09fcfcbb4f62da3c2927435233c