List of screens reported has less screens than actual if Device Name not unique

For the windows platform, `QWindowsScreenManager::handleScreenChanges()` checks if a screen is not already in the list by comparing against `newData.deviceName`.

This device-name is not guaranteed to be unique however: Since this is queried internally from windows via the `szDevice` field from the `MONITORINFOEXA` structure (see the `monitorData` function also in `qwindowsscreen.cpp`). - See also this stackoverflow question: How can I uniquely identify a monitor? - Stack Overflow

The discussed behaviour can cause problems (up to a access violation / crash) when, for example, you ask which screen a window is on, and it happens to be one of the discarded ones (since there can only be one with that device name).

As a result, we believe we have been unable to fix a bug (as a workaround) where a sub-window doesn't want to open over the main window.

More seriously, but also more tentatively, we think it may indirectly be responsible for a number of crashes.

For completions sake, I'll attach a list of the github issues reported by our users (though I don't suspect you can do much with it, as it's very indirect):

https://github.com/Ultimaker/Cura/issues/11907
https://github.com/Ultimaker/Cura/issues/12102
https://github.com/Ultimaker/Cura/issues/12248
https://github.com/Ultimaker/Cura/issues/12264
https://github.com/Ultimaker/Cura/issues/12197
https://github.com/Ultimaker/Cura/issues/12306

(While there where a lot of seemingly similar issues in the bug-tracker, I could not find this particular one. I also hope that the code-analysis is enough, but I'm willing to put in the time for a complete reproduction if really required.)