Fix #29451: Layout fermatas cross-staff

[XiaoMigros]

Resolves: #29451

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[its-not-nice]

Thanks! This works well for unbeamed notes and is a welcome improvement:

Less good in cross-staff situations where they often need to be moved outside the beam. Compare the marcatos, which are behaving themselves:

In any case, a vtest illustrating various situations would be very welcome here.