Summary:
Migrates all usages of `NativeEventEmitter` to `NativeEventEmitter<$FlowFixMe>`.
This prevents having to modify a very large number of files in the same change that adds support for typed events. It adds an unused typed parameter to `NativeEventEmitter` so we can change all usages to add `$FlowFixMe`.
Changelog: [Internal]
Reviewed By: nadiia
Differential Revision: D25575774
fbshipit-source-id: c7979e1502e980401d9c03456282eba333c1606d