Copy/Paste commands (both from the "Edit" menu and keyboard shortcuts) don't work in the "Save score" dialog

### Issue type UX/Interaction bug (incorrect behaviour) ### Description with steps to reproduce Notes: - Not sure if it's a general issue or macOS-only. - I am aware of other open tickets regarding shortcuts being broken in some cases, but in this case, the commands from the "Edit" menu don't work either. - This is not a regression – it never worked. It's just that my annoyance level with this bug reached its limit, so I decided to report it. :) Desctiption: - Copy/paste from the clipboard (from the app menu, as well as Cmd-C / Cmd-V / Cmd-X shortcuts) doesn't work in the "Save score" dialog. - The system clipboard works, though – in the same dialog, you can open the system popup by right-clicking, and "Cut" / "Copy" / "Paste" work just fine from there. - As far as I can tell, MuseScore is the only app on macOS that has this issue in the "Save" dialog – I have never encountered this anywhere else. **Repro** 1. Create a new project in MuseScore. 2. Make sure that some text is copied to the clipboard (e.g., select some text in MuseScore itself and use its "Copy" function from the "Edit" menu). 3. Click "File" > "Save" > "Save to computer". 4. Press Cmd-V or select "Paste" from the "Edit" menu. **Expected** - The previously copied text is pasted into the file name field. **Actual** - Nothing happens. You can also verify that the copied text is still in the clipboard by clicking "Paste" in the right-click system popup menu or by trying to paste it anywhere in MuseScore after closing the "Save" dialog. ### Supporting files, videos and screenshots https://github.com/user-attachments/assets/ea540168-343a-4c5b-8840-6c810d7c7d93 ### In which versions of MuseScore Studio is this issue present? 4.7.4-260706075, revision: github-musescore-musescore-7688c00 ### Regression Choose option... ### Operating system macOS Tahoe (26.5.2) ### Additional context https://github.com/user-attachments/assets/0d091e01-8adc-4bff-9f36-d85b5f6d081a ### Checklist - [x] This report follows the [guidelines](https://github.com/musescore/MuseScore/wiki/Reporting-bugs-and-issues) for reporting bugs and issues - [x] I have verified that this issue has not been logged before, by searching the [issue tracker](https://github.com/musescore/MuseScore/issues) for similar issues - [x] I have attached all requested files and information to this report - [x] I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible