Summary:
added protection for emit() because subscription.listener may have been removed during event loop
Changelog:
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[GENERAL][FIX] Avoid crash when subscription listener may have been removed during event loop
Pull Request resolved: https://github.com/facebook/react-native/pull/23047
Differential Revision: D13761725
Pulled By: cpojer
fbshipit-source-id: 0753b780067bd712cd43caf63020c3f0d6ea9f52