fix: Make race condition between channel open and RPC less likely to …

…occur (#5514)

Right now we rely on opening the channel to associate a ClientId with an
entry on the gateway side. This causes a race when the channel is being
opened in the background while an RPC (e.g. MyAgent.register()) is
invoked.

If the RPC is processed first, the gateway rejects it due to "invalid"
clientId.

This fix makes this condition less likely to trigger, but there is still
a piece of the puzzle that needs to be solved on the Gateway side.

.github/workflows/checks.yml

@@ -183,7 +183,7 @@ jobs:
 
   codecov:
     runs-on: ubuntu-latest
-    needs: [test]
+    needs: [test, test-grpc]
     strategy:
       matrix:
         package: