Changed touch detection for Workspace button

[Thesola10]

This fixes #992 by triggering the button action at the start of the touch event, rather than at the end.

@ShamrockLee please test

[github-actions]

Thanks for your contribution! We don't accept pull requests to the release branch. I have rebased your pull request onto develop, check for any conflicts.

[ShamrockLee]

Thank you very much for being so patient. I recently updated the SSD of my tablet and is now reinstalling the system. It would take some time before I could test this.

As for the change, I hope that we could eventually find a solution that uses the up-event instead of the down-event for short tapping buttons in the long run. A button triggered by the up-event allows aborting by dragging the touch pointer away from the button before lifting, and is therefore more fault-tolerant and more accessible to users with physical disability (ref. WCAG 2.1 2.5.2 Pointer Cancellation).