calib_dlg: fix checkbox styling

[buzzhuzz]

Description

Do not set custom font and colour for checkbox caption labels. Update checkbox caption labels visibility depending on checkbox enabled state

Screenshots/Recordings/Graphs

Original behavior:

Updated behavior:

Tests

Linux with light theme only.

[buzzhuzz]

@Patn1, please check if this PR resolves your issue you've brought up in #7199 (comment)

[Patn1]

Thank you for tagging me and trying to optimise it. But I cannot really test this because the artefact only contains this PR without your other PR. So I may have to wait until the other is merged.

[buzzhuzz]

Oh, I see. Just pushed merged 7289 and 7199 into my fork https://github.com/buzzhuzz/OrcaSlicer/tree/refs/heads/test/orca-pr7289-validation
You could get binaries to test once the build is complete at https://github.com/buzzhuzz/OrcaSlicer/actions/runs/11621615427

[Patn1]

Definitely better than before, but I think that its still not perfect.

Also it looks worse in dark mode now.

I don't know if it's possible, but could it be made like the slicer settings? So that the checkbox also has a white background when its selectable or a grey background when its not?