[native] Update ComposeThread to use navigation.getParam
[native] Update ComposeThread to use navigation.getParam

Did this in preparation for https://github.com/react-navigation/react-navigation/pull/5074, and to test it

Ashoat/squadcal,Ashoat/squadcal,Ashoat/squadcal,Ashoat/squadcal,Ashoat/squadcal,Ashoat/squadcal,Ashoat/squadcal