fix a forgotten nonce

[dzmuh97]

Pull request summary

After we subscribe to topics we wait for the event_pubsub_nonce, but it is not called because the server does not pass the nonce it should return in response to the client, which we wait for in websocket.py:200

Checklist

• [x] If code changes were made then they have been tested.
  • [ ] I have updated the documentation to reflect the changes.
  • [x] I have updated the changelog with a quick recap of my changes.
• [x] This PR fixes an issue.
• [ ] This PR adds something new (e.g. new method or parameters).
• [ ] This PR is a breaking change (e.g. methods or parameters removed/renamed)
• [ ] This PR is not a code change (e.g. documentation, README, ...)

[chillymosh]

This is most likely because the nonce is optional here, so was either overlooked or deemed not necessary at the time.

It doesn't prevent the use of the extension.

[chillymosh]

@dzmuh97 could you please complete the PR request