"Use previous settings" leave you with messed up windows

### What Happened?

"Use previous settings" does not restore window size and position on screens.

Now most of my browser windows are tiny on the second screen!


### Steps to Reproduce

1. Have 2 displays, one 2.5K and one 2K (Full HD). Have many browser windows open on both
2. Enable mirroring. It will enable 3x scaling because of https://github.com/elementary/switchboard-plug-display/issues/273
3. Click "Use previous settings" or wait

### Expected Behavior

Restore windows to previous size/position

Everything should be the same as before using some horribly broken setting. That's what "Use previous settings" is for and it does not work!

### OS Version

6.x (Odin/Jólnir)

### Software Version

Latest release (I have run all updates)

### Log Output

_No response_

### Hardware Info

_No response_

Start by reproducing the two-display setup with mirroring and 3x scaling, then follow the window handling used by “Use previous settings.” Compare window size and position before and after restoring the display configuration. Done means windows return to their previous size and position instead of becoming tiny on the second screen.

Written by the indexing model from the issue text.