Regression: basic touchscreen events are broken (can't tap, can't scroll up)

### What Happened?

I upgraded from Elementary OS 5.1 to Elementary 6.1 and I can't use my touchscreen anymore:

- tap has no effect: it never triggers any button despite triggering visual feedback.
- one finger up opens one of the multi-tasking view (the workspace editor?).

See https://elementaryos.stackexchange.com/questions/29958/touch-screen-single-figure-or-double-finger-gestures-on-inside-specific-window-a for pictures and a video from somebody else having the exact same problem.

### Steps to Reproduce

1. Install a fresh Elementary OS 6.1
2. Open an application
3. Tap anything on the screen with 1 finger: there is visual feedback, but buttons are never clicked.
4. BUG 2: try to scroll up with 1 finger: the workspace editor view opens.

### Expected Behavior

- Tapping a button should trigger a click on that button.
- Moving ONE finger up should work just like the other directions (down, left, right): scroll.

### OS Version

6.x (Odin)

### Software Version

Latest release (I have run all updates)

### Log Output

_No response_

### Hardware Info

Dell XPS 15 9530

It worked perfectly in Elementary OS 5.