remove one_sided_type_guards option from flowconfigs (on by default)

Summary:
X-link: facebook/react-native#45349

This is on by default as of version 0.239.0:

https://github.com/facebook/flow/blob/v0.239/src/commands/config/flowConfig.ml#L268

Changelog: [Internal]

Reviewed By: SamChou19815

Differential Revision: D59525192

fbshipit-source-id: b4bf456e3c03a712f4c6f5d72d157b3abf8f9895

.flowconfig

@@ -14,8 +14,6 @@ enums=true
 
 module.name_mapper='\(metro-[^/]*\)' -> '<PROJECT_ROOT>/packages/\1/src/index.js'
 
-one_sided_type_guards=true
-
 suppress_type=$FlowIssue
 suppress_type=$FlowFixMe
 suppress_type=$FlowFixMeProps