updated docs with platform-specific behaviors (#502)
updated docs with platform-specific behaviors (#502)

The behavior of ReauthenticateAndRetrieveData errors differ per platform. The preexisting comments documented the iOS behavior only, which was confusing for users of other platforms.

This PR clarifies that errors on Android and Desktop platforms may cause the user to be signed out.
firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk