"Use all voices on this staff" voice assignment shouldn't enable reset button on single-staff instruments

Issue type

UI bug (incorrect info or interface appearance)

Description with steps to reproduce

Dynamics/hairpins on single-staff instruments only have a single "All" option under the "Voice assignment" property, whereas on grand staff instruments there are two options ("All voices on instrument" and "All voices on this staff").

In the backend, "All" on a single staff instrument is the same as "All voices on instrument" on a grand staff instrument, and this is the default setting of the property.

So if you copy a dynamic from a grand staff instrument set to "All voices on this staff" to a single-staff instrument, in properties "All" is still selected but the Reset button is turned on because technically it's still not the default. You can also trigger this state using the "Use all voices on this instrument" shortcut (Ctrl + Alt + - OR Cmd + Opt + -).

The reset button should not be enabled in this case on the single-staff instrument, because to the user, there's only one "All" option and nothing is actually getting reset.

It should work something like this:

• The dynamic is set to "All voices on instrument" (or "All" on a single-staff instrument)
  • Reset button is disabled
• The dynamic is set to "All voices on this staff"
  • Is the instrument a single-staff instrument?
    • YES: Reset button is disabled
    • NO: Reset button is enabled (i.e. it's on an instrument with more than one staff)

Elements affected:

• Dynamics
• Hairpin: Crescendo hairpin
• Hairpin: Crescendo line
• Hairpin: Decrescendo hairpin
• Hairpin: Decrescendo line

Supporting files, videos and screenshots

https://github.com/user-attachments/assets/e43bf46b-06d8-412b-b482-9b2866df6874

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

Nightly Aug 12

Regression

No.

Operating system

macOS 14.5

Additional context

No response

Checklist

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

No source file or test is named in the issue. Start by reproducing the voice-assignment and Reset-button states for dynamics and each listed hairpin type on single- and grand-staff instruments; done means the Reset button stays disabled for the single-staff cases and remains enabled for “All voices on this staff” on multi-staff instruments.