NEW Score Wizard Choose Instrument Panel: Selecting with keyboard Adds the instrument making the Add Button confusing

Issue type

Accessibility issue (e.g. for keyboard-only or screen reader users)

Description with steps to reproduce

In the New Score Wizard, using the Choose Instruments, assume you find an instrument you want to add; there is no Add Instrument button until after an instrument is selected using space or enter. At that point a screen reader does not realise that when they pressed space/enter the instrument was added to their score and will tab forward and find the now available Add button and likely press it again adding a second one of the same instrument.

Note: see related issues currently under work at #15521.

Steps:

1. From the File menu select New, or press Ctrl+N.
   The New Score wizard appears.
2. Select Choose Instruments. NB: At this point it opens on a search box which seems to disapear as soon as it is moved away from and very strangely you have to search around to find the lists back from where you are focused when the window opens.
3. Select any desired category, such as Woodwinds.
4. Arrow Down from Search to find an instrument, e.g. Flute.
5. Tab around the dialog and there is no Add Instrument button.

Expected behaviour: When an instrument is selected in the search results, the Add Instrument button should be available and tabbable. In lists being arrowed through it is usually assumed the item you finish on when you tab away from it is selected.

Actual behaviour: there appears to be no available Add Instruments button.

It would be desirable if either the item was selected with arrow movement as described above and the Add button used to add to the score. however, if it will require pressing space/enter to select then either this should not add it to the score and the Add button still be required or if it is going to Add it then the screen reader should announce that it has been added when the instrument is selected.
Note it is also more usual to announce items that are selected rather than saying "not selected on every item".

Supporting files, videos and screenshots

N/A

What is the latest version of MuseScore Studio where this issue is present?

4.5.2

Regression

I was unable to check

Operating system

Windows 11

Additional context

No response

Checklist

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• I have attached all requested files and information to this report
• I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible