ComposeBox: Add onLayout callback to adjust autocomplete.
ComposeBox: Add onLayout callback to adjust autocomplete.

This callback will set height in the state which is then
applied to Autocomplete wrapper as a marginBottom.
So that auto complete always floats above compose box.

vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile