[iOS] Support RN 0.46+, #1121 (#1122)
[iOS] Support RN 0.46+, #1121 (#1122)

* [iOS] Support RN 0.46+, #1121

* [iOS] Use bridge dispatchBlock, thank @javache, refs #1121

* [iOS] Drop unneeded expose of private methods for RCTBridge, refs #1121

realm/realm-js,realm/realm-js,realm/realm-js,realm/realm-js,realm/realm-js,realm/realm-js,realm/realm-js,realm/realm-js,realm/realm-js