Fix #290409 - Stave brackets disappear on a 1 line percussion staff

[njvdberg]

Resolves: https://musescore.org/en/node/290409

Original code was using the height of the staff to calculate the hight of the
brackets. But for single line staff (percussion instruments!) there is only one
line, resulting in a height of zero, meaning a height of zero.
Now, for single line staves, the height of the barlines is taken. Since barlines
can span several staves in a system the calculation of the barline height has to
implemented in this code itself.
By setting the correct bbox and yOffset for the SysStaff object, this changes will
affect the layout of the system. Compared with version 3.4 all staves of a system
are on exactly the same position.

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[anatoly-os]

@njvdberg would be great to add visual tests for the change. The cases from the related issue can be used. Should you have time, please add ones in a separate PR.

[njvdberg]

Sure, no problem, see PR #5983 .