Prepare to switch to using (the future) Drupal 9 JSON:API endpoint - implement tests, etc.

Adjusted title slightly as this issue is exactly what I am working on. Assigning to me. I will create an issue fork so we can see the progress.

Note that it is built from the changes introduced here: https://www.drupal.org/project/project_browser/issues/3278352

The referenced issues changes are added to this MR as they're useful/needed.

Waiting for related issues to go through as this one relies on those.

Include the correct namespace for composer as separate property here too.

I have moved the plugin in project_browser_test module in MR#308. May be some other work needs to be done here hence not changing assignee/Status.

Added some more feedback, really small.

Actually, the only reason why I was assigned to it was to make sure I was able to keep up with the rest of PB changes on this issue, but as we're now making ready to be in the module, there is no need to have me as assignee.

Other than the small feedback I added, I think we can start asking for reviews. @narendraR, @bnjmnm and myself have worked on it, so maybe a further review from @tim.plunkett would be great.

MR#308 is the one to review.

Addressed feedback and marking as needs review.

Integrated the new logo field, which will be a separate field on projects on the new www.drupal.org D9/10 version.

This was a follow-up from #3334783: Integrate GitLab Logo png to Drupal.org D7 project pages and #3334807: Repository logo on projects pages styling as the repo gitlab avatar is now displayed on the project pages.

This is fantastic progress.

I think we just need to be aware that when this is promoted to the D9 endpoint, it will have the effect that many projects that have logos in the first image will lose their logos in Project Browser.

We can just define the policy here #3277464: [PLAN] Where to fetch image from? and then implement the logic in this issue.

We can just fetch from the new D9 logo_url field (this is what's done right now), or add a fallback if needed.

As for the "losing" logos, taking a first image as a logo doesn't make it a logo (there are some comments about it in the linked issue). Maintainers that do worry about their logo will quickly update, and as far as I know, all the logo suggestions that we will make to the top 100 will also be made with the recommendation of adding it as logo.png to the repo.

Once users start seeing their modules showing up in project browser, they'll change logos, descriptions, etc and the advantage of the live endpoint is that the changes will show up in real-time.

In any case, I'm happy to implement whatever is decided.

Correct Chris. It's not part of the json output.
On D7, we check it (and cache it) on the fly from the gitlab avatar URL, no field required.
On D9, this is a field that checks the above URL, and populates it.

We could alter the fixture generation to check the gitlab avatar and set it as logo. That won't be a difficult one. I'm happy to address it (best on a separate issue).

I think it might also need a rebase? :)

It seems that markup has changed and the CSS selectors in the tests are no longer up to date. I will try to work on them.

Ok, a lot of markup changed since the test was written.
All feedback that was given at DrupalCon was addressed and all the tests have been fixed.

Ready to review again.

Reviewed the code for the JSON:API source. Seems there is an testing issue left though.

Tests are green now. I forgot to propagate the change to another part of the file. I love having tests.

Went through the last commits, changes look as expected. Only a small comment on a comment (lol), but that is probablly nothing.

RTBC if i may ;)