AppEventHandlers: Add fixme for bug in a flow-typed definition.
AppEventHandlers: Add fixme for bug in a flow-typed definition.

The flow-typed definition in question only applies to Flow >=0.68, so
we'll get it with the RN 0.56 upgrade.

The README for react-native-orientation, the actual library being
described, clearly says this callback will always be passed a string
argument (indeed, one of a small fixed set.)

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