Rethrow MSAL AuthErrors in NAA flow

[salaman]

NAA flow catches errors and runs them through fromBridgeError, but not all errors in the try come from the bridge. Notably, fromNaaTokenResponse can throw a ClientAuthError if a token is empty, and cache codepaths can throw some CacheErrors.

This PR ensures that if an error is already an MSAL AuthError, it does not get passed through fromBridgeError again and converted into an unknown_error.