chore: Reduce the number of jobs running on PR triggers

[EmandM]

Reduce the number of jobs that are running on each PR from 43 jobs to 26.

Changelog

• Changed: Updated the automated test configuration.

Testing and Documentation

Backport

Up ported by #3545

[NoelStephensUnity]

Looks good to me.

@michalChrobot
Could you review over this PR? We are migrating away from running 2021.3 during normal PRs (still runs weekly) to reduce the over-all PR time.

[michalChrobot]

Yeah, I remember talking about reducing test overhead on PRs @EmandM but I didn't have time to get to it so thanks for doing this!

Makes sense to me, what we are doing in essence (is anyone else will stumble upon this PR) is

• Migrating slowly to 2022.3 editor since 2021.3 will stop being supported in +- October. For now those tests will still run nightly so it's still covered but should start getting less attention
• Running project/package tests on latest and oldest supported editor per each platform is replaced by specifically targeting combinations which should get us the same coverage (worst case all tests still run nightly but won't block PRs). The distribution times got quite high those days so this should help in reducing waiting time on PRs

Really nice improvement in terms of numbers!

[michalChrobot]

I noticed that we progressed in editor versions so I used this occasion to add 6000.2 to the list of supported editors. Notice that this will only influence nightly/weekly tests and nothing PR related