RN0.64 42/*: Turn off types_first in native

Summary: This silences ~1000 errors and lets us move forward with the React Native 0.64 upgrade without blocking on `types_first`. (I'll try to figure out `types_first` as a later step.)

Test Plan:
I tested the whole upgrade together:

1. Compile and run iOS and Android on release and debug
2. Make sure Flow typechecks
3. Make sure debugging tools still work

Reviewers: palys-swm

Reviewed By: palys-swm

Subscribers: KatPo, Adrian, atul

Differential Revision: https://phabricator.ashoat.com/D1738

native/.flowconfig

@@ -49,6 +49,8 @@ suppress_type=$FlowFixMe
 suppress_type=$FlowFixMeProps
 suppress_type=$FlowFixMeState
 
+types_first=false
+
 [lints]
 sketchy-null-number=warn
 sketchy-null-mixed=warn