Fix #27582: Fix removing timeSig from mmRests

[prodoelmit]

• Adds additional check to remove timeSig segment from inside mmRest

Resolves: #27582

Fixes the case where removing time signature that is only followed by multi-measure rests (even if it's 1-measure mmRest) crashes the application

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• Each commit's message describes its purpose and effects, and references the issue it resolves
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[zacjansheski]

Tested on MacOS 15, Windows 11, Ubuntu 22.04.3. Approved
#27582 FIXED

[RomanPudashkin]

@prodoelmit thank you!