update tests for 3.14

[minrk]

• move qt matrix out of hatch to CI because qt6 doesn't work on 3.14 and hatch doesn't seem to be able to exclude matrix entries (and we don't use the hatch matrix for anything else)
• skip 3.14t which needs a jupyter-core release (coming soon)
• test less than all combinations of Python + qt
• the subprocess output capture tests seem to not work on 3.14. I don't understand why because the same code definitely does work perfectly in a notebook. Maybe conflicting somehow with pytest's FD output capture. So those tests are now skipped, but it's the test that is broken, not the actual behavior.

[minrk]

note: this doesn't increase the size of the build matrix, it actually shrinks it. What it does is shift a dimension of the matrix (qt5 or qt6) up from hatch to github, so we can do things like skip qt6 on 3.14 (and skip some others because we don't need every qt on every version, as long as we have upper/lower bounds covered)

[ianthomas23]

Thanks @minrk

[ianthomas23]

Note to self (or someone else if they beat me to it): needs backport to 6.x branch

[ianthomas23]

@meeseeksdev please backport to 6.x

[lumberbot-app]

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

git checkout 6.x
git pull

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 93f11dbb02692a7922cb6fdb4ebadffdb8b691c0

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am 'Backport PR #1453: update tests for 3.14'

4. Push to a named branch:

git push YOURFORK 6.x:auto-backport-of-pr-1453-on-6.x

5. Create a PR against branch 6.x, I would have named this PR:

"Backport PR #1453 on branch 6.x (update tests for 3.14)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.

[ianthomas23]

Manually backported by #1460.