[BUG] Studio creates extra notes when tying consecutive grace notes together

Issue type

Crash or freeze

Description with steps to reproduce

Steps to Reproduce

(Edit from @mathesoncalum) Scenario A was resolved in #34836

Scenario A: Crash (Grace notes before parent note)

1. Create a measure with a single parent note (e.g., C5).
2. Insert two consecutive grace notes of the same pitch (e.g., G4 and G4) directly before the parent note.
3. Ctrl-click (or Cmd-click) to select both grace notes.
4. Attempt to add a tie between them (press T or use the palette/toolbar).
5. Result: MuseScore Studio crashes immediately.

Scenario B: Unexpected note creation (Grace notes after parent note / acciaccatura / after-grace)

1. Create a measure with a single parent note (e.g., C5).
2. Insert two consecutive grace notes of the same pitch (e.g., G4 and G4) attached after the parent note.
3. Ctrl-click to select both grace notes.
4. Attempt to add a tie between them.
5. Result: Instead of tying the grace notes, MuseScore Studio creates duplicate new notes with the pitch of the grace notes in the main measure.

Expected Behavior

• Selecting two adjacent grace notes of identical pitch and applying a tie should cleanly connect them with a tie curve.
• Applying ties across grace notes should not crash the application or generate unintended full-sized notes in the score.

Supporting files, videos and screenshots

• diag.zip
• crash.mp4
• duplicate.mp4
  (had to do this because somehow github failed to upload mp4 files)

In which versions of MuseScore Studio is this issue present?

4.7.4-260706075 (64-bit)

Regression

I was unable to check

Operating system

Windows 11 (25H2 or later), x86_64

Additional Context

• The handbook contains no specific guidelines regarding restrictions on tying grace notes together.

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