Shortcut Keys not Advertised to Screen Readers in Palettes

[jmwmusic]

Issue type

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

Description with steps to reproduce

A small number of Palette items either have default, or can have custom keyboard shortcuts assigned. For example Layout palette; Insert system break. It would be helpful if these were advertised to the screen reader.

STEPS:

1. With screen reader such as NVDA enabled navigate to the Layout palette and arrow down to System Break.
2. Notice the screen reader just announces System Break and does not read the available shortcut. It should say "System Break, Ctrl + Enter".

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

• [x] This report follows the guidelines for reporting bugs and issues
• [x] I have verified that this issue has not been logged before, by searching the issue tracker 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

[sand1024]

@dxli I'll take a look to this. Most probably it's due to the historical mess with nullptr graphics for a block editing...

UPD: I've fixed this locally, so will commit as larger MR