Add a staff to an other which contains a local time signature causes a crash

Nightly December 26: 273bd61 / Windows 7

1. On "My First Score" , fill the first measure (4/4) with some notes, or open this file : Test Add a staff.mscz

2. Drag and drop a local time signature 3/4 (with Ctrl) in the second measure – no need to fill with notes.

3. « I » → Select first staff → Add a staff (bass clef) → Ok

Result : crash

It's probably related with this issue: #41796: Crash when adding a Global time sig into a measure which is in Local time sig. But it is not a duplicate, because the simple fact to add a local Time Sig in a staff causes a crash by adding an other staff.

An additionnal proof ? With this specific scenario, the crash occurs a few months earlier.

More precisely between July 29 with this Nightly, correct: ccb04e0
-

- and this one, on July 30, with a failure: e7e9d9f

For fix this issue: #25876: Local time signatures have incorrect beaming and can cause score corruption

So the origin maybe is here: https://github.com/musescore/MuseScore/commit/bc891168eb43e459685a7c045…

or/and here, less likely? https://github.com/musescore/MuseScore/commit/f7bea5e2671460ffd98a56c21…

- Note that there is no crash by adding a linked staff, but the corruption is always underlying by mixing afterwards different types of TimeSig (local / global), e.g:

1 measure 4/4 global + 1 measure 3/4 local + 1 measure 4/4 global, with bad consequences later.