fix #8935 - Slurs, ties, lines extend beyond final barline

[asattely]

Resolves: #8935

The margin before the final barline is hardcoded for now, but it is only in one place, so it's very simple to refactor later if it becomes a user-facing parameter. For now, it is 0.25sp.

[its-not-nice]

The gliss line remains a problem here (though the tie is spot on):

This sample file at: https://musescore.org/en/node/319761

[Jojo-Schmitz]

What about non-normal barlines, most notably end repeat? Now looks like this:

[its-not-nice]

Looks good to me. If you mean that the lines could end later if they are in no danger of colliding with the dots, I feel it is better that they all end at a consistent point by default. Otherwise one could end up with a situation like this:

Also, the dots are clearer if they do not become enclosed by other symbols.

[Jojo-Schmitz]

Why is this not getting merged?