[23.2] Limit new anon histories

[mvdbeek]

This is a two-fold fix that should reduce the number of newly created histories.

• When we first create a new session (e.g. because an initial session cookie hasn't been provided or wasn't valid) we don't create a new history or associate an existing history. Scripts or spiders that don't include a session cookie will not be creating new histories that way.
• Do return the default history also for anon users in get_or_create_default_history

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[mvdbeek]

That's a lot of failing tests, but I think they're all unrelated, the integration tests should all be fixed by #17679

[davelopez]

It works correctly on my local testing. There is still a tiny chance of a race condition if the first request doesn't create the history before the next request kicks in but it is much much better now!

Thank you!

[bernt-matthias]

This apparently broke planemo serve #17821