Fix memory leak in RCTSafeAreaView
Fix memory leak in RCTSafeAreaView

Summary:
According to the retain code collector, RCTSafeAreaView is in a cycle:
-> _bridge -> RCTCxxBridge -> _moduleDataByName -> __NSDictionaryM -> RCTModuleData -> _instance -> RCTUIManager -> _viewRegistry -> __NSDictionaryM -> RCTSafeAreaView
This should break the cycle.

Reviewed By: shergin

Differential Revision: D6213668

fbshipit-source-id: efb9c1dd148b72f66fe4485b81c16cd4c2d18b17

arthuralee/react-native,facebook/react-native,ptmt/react-native-macos,Bhullnatik/react-native,kesha-antonov/react-native,rickbeerendonk/react-native,exponent/react-native,arthuralee/react-native,hoastoolshop/react-native,facebook/react-native,dikaiosune/react-native,pandiaraj44/react-native,hoangpham95/react-native,facebook/react-native,myntra/react-native,kesha-antonov/react-native,facebook/react-native,javache/react-native,hammerandchisel/react-native,arthuralee/react-native,exponent/react-native,dikaiosune/react-native,facebook/react-native,myntra/react-native,dikaiosune/react-native,exponentjs/react-native,exponent/react-native,pandiaraj44/react-native,pandiaraj44/react-native,kesha-antonov/react-native,javache/react-native,janicduplessis/react-native,pandiaraj44/react-native,ptmt/react-native-macos,dikaiosune/react-native,facebook/react-native,exponentjs/react-native,ptmt/react-native-macos,myntra/react-native,cdlewis/react-native,rickbeerendonk/react-native,exponentjs/react-native,Bhullnatik/react-native,hoastoolshop/react-native,kesha-antonov/react-native,exponentjs/react-native,Bhullnatik/react-native,cdlewis/react-native,dikaiosune/react-native,kesha-antonov/react-native,dikaiosune/react-native,hammerandchisel/react-native,hammerandchisel/react-native,jevakallio/react-native,javache/react-native,hoangpham95/react-native,facebook/react-native,exponent/react-native,rickbeerendonk/react-native,exponent/react-native,kesha-antonov/react-native,jevakallio/react-native,myntra/react-native,myntra/react-native,Bhullnatik/react-native,myntra/react-native,hammerandchisel/react-native,kesha-antonov/react-native,hammerandchisel/react-native,hoangpham95/react-native,Bhullnatik/react-native,cdlewis/react-native,janicduplessis/react-native,javache/react-native,hammerandchisel/react-native,exponentjs/react-native,hoastoolshop/react-native,janicduplessis/react-native,ptmt/react-native-macos,javache/react-native,jevakallio/react-native,jevakallio/react-native,ptmt/react-native-macos,cdlewis/react-native,pandiaraj44/react-native,jevakallio/react-native,pandiaraj44/react-native,facebook/react-native,jevakallio/react-native,javache/react-native,rickbeerendonk/react-native,janicduplessis/react-native,exponent/react-native,jevakallio/react-native,hoastoolshop/react-native,cdlewis/react-native,javache/react-native,hoangpham95/react-native,ptmt/react-native-macos,javache/react-native,myntra/react-native,hammerandchisel/react-native,pandiaraj44/react-native,janicduplessis/react-native,hoastoolshop/react-native,rickbeerendonk/react-native,arthuralee/react-native,hoangpham95/react-native,kesha-antonov/react-native,kesha-antonov/react-native,cdlewis/react-native,rickbeerendonk/react-native,dikaiosune/react-native,janicduplessis/react-native,janicduplessis/react-native,arthuralee/react-native,Bhullnatik/react-native,pandiaraj44/react-native,exponentjs/react-native,facebook/react-native,javache/react-native,hammerandchisel/react-native,janicduplessis/react-native,cdlewis/react-native,jevakallio/react-native,hoangpham95/react-native,Bhullnatik/react-native,ptmt/react-native-macos,hoangpham95/react-native,rickbeerendonk/react-native,exponent/react-native,rickbeerendonk/react-native,jevakallio/react-native,cdlewis/react-native,myntra/react-native,hoastoolshop/react-native,dikaiosune/react-native,exponent/react-native,exponentjs/react-native,Bhullnatik/react-native,rickbeerendonk/react-native,exponentjs/react-native,ptmt/react-native-macos,hoastoolshop/react-native,myntra/react-native,hoangpham95/react-native,hoastoolshop/react-native,cdlewis/react-native