EDMarketConnector: invalidate companion session and return on CredentialsError

* If we don't invalidate then the companion.Auth code will do nothing
  due to "already auth'd".
* We need to give the auth flow time to complete, so need to return.
* As that auth flow can take indeterminate time, not setting a timed
  retry of the CAPI query here.  We should consider setting a flag and
  reacting in the Auth code though.

EDMarketConnector.py

@@ -1114,7 +1114,9 @@ class AppWindow(object):
         except companion.CredentialsError:
             companion.session.retrying = False
             # TODO: Might need to .invalidate() here to avoid "already auth'd"
+            companion.session.invalidate()
             companion.session.login()
+            return
 
         # Companion API problem
         except companion.ServerLagging as e: