[PR #5637/6fb3efc backport][3.8] Update client/server implementation in the autobahn tests

[wfatherley]

This is a backport of PR #5637 as merged into master (6fb3efc).

What do these changes do?

Alters autobahn client and server tests by updating deprecated syntax

Are there changes in behavior for the user?

No, there should not be

Related issue number

Resolves #5606

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• If you provide code modification, please add yourself to CONTRIBUTORS.txt
  • The format is <Name> <Surname>.
  • Please keep alphabetical order, the file is sorted by names.
• Add a new news fragment into the CHANGES folder
  • name it <issue_id>.<type> for example (588.bugfix)
  • if you don't have an issue_id change it to the pr id after creating the pr
  • ensure type is one of the following:
    • .feature: Signifying a new feature.
    • .bugfix: Signifying a bug fix.
    • .doc: Signifying a documentation improvement.
    • .removal: Signifying a deprecation or removal of public API.
    • .misc: A ticket has been closed, but it is not of interest to users.
  • Make sure to use full sentences with correct case and punctuation, for example: "Fix issue with non-ascii contents in doctest text files."

[webknjaz]

@wefatherley thanks for the backport PR. I only have one minor comment for the future: it's best to use meaningful PR titles relating to the original PR, not just the branch name it's sent against.

[wfatherley]

@webknjaz sure thing. Sorry about the title, I'll be sure in the future to set the title going forward. Thank you for this tip also :)