mouse: Transform the "Test Settings" button into a floating button
requested to merge automerisnaranja/gnome-control-center:mouse-floating-test-settings-button into main
Doing so, this button won't be hidden at the very end of the Mouse & Touchpad pages.
Also:
- Use a single CSS file for the entire panel to avoid using multiple CSS files
- Since this button is no longer in the headerbar, remove its tooltip, because that HIG guideline that says "controls in the header bars of primary windows should all have tooltips" is no longer applicable
| Dark | Light |
|---|---|
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Closes #2923
Edited by Automeris naranja