Shadow note couple fixes

[sammik]

Resolves easier ones of #14815

• ledger lines spaces in customised line space staves
• ledger line width in scaled staves
• dotted rest dot position in scaled staves

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• I created the test (mtest, vtest, script test) to verify the changes I made

[RMRattray]

Can confirm that issues 4-7 still occur; as such, I'd like to work on them if I might.

[cbjeukendrup]

@RMRattray feel free to! That would be appreciated. (I can't assign you yet though because you commented on this PR rather than on the issue 🙂)