docs: mention AppCompatActivity constraint with Expo #526

Job	Run time
Check changeset	1m 22s
Build & static code analysis	1m 55s
iOS road test (RNApp & AppleApp - Vanilla)	8m 26s
iOS road test (RNApp & AppleApp - Expo)	23m 50s
Android road test (RNApp & AndroidApp - Vanilla)	25m 18s
Android road test (RNApp & AndroidApp - Expo)	46m 24s
iOS road test (TesterIntegrated)	6m 55s
Android road test (TesterIntegrated)	15m 0s
	2h 9m 10s

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