Summary:
Changing FlipperRSocketResponder to only use public parts of FlipperConnectionManagerImpl.
This means we can test it by injecting a FCM mock, and it can use its public interface.
Reviewed By: passy
Differential Revision: D14000078
fbshipit-source-id: c0431a888b0ca041807631c81b99fb8b947274d6
5da8f35ee3