Fix GH#24998: cannot use shortcut (show-corrupted-measures)

[Jojo-Schmitz]

Resolves: #24998

[Jojo-Schmitz]

Not really sure about this, having it set to true seems a sane default for debug and non-debug builds, esp. as that setting doesn't seen to get saved accross sessions, so needs to get enabled time and time again (in non-debug builds).

An alternative or additional option might be to have a a checkbox in the 'Corrupt score' dialog, to enable this setting right when it is needed, or even enable it there without asking the user in case of a corrupted score, or even each time a corrution is found.

Ideas welcome ;-)

[cbjeukendrup]

As a "stretch goal", we could do the following:

• Indeed, make this option true by default
• Add a command to (re-)check for corruptions (current workaround is to wait until Autosave runs, because that also checks for corruptions, but does not warn about them in the UI, and it is questionable whether Autosave is supposed to run the corruption check at all)
• For optimisation, set a member variable in the Score whether it contains any corrupted measures; if that's false, no need to iterate over all measures to find corrupted ones

[Jojo-Schmitz]

The true by default is dead easy, I'll do it right way
Not sure how to go about adding such a command (will look into it), but indeed autosave shouldn't run that check or report them right away.
The optimization won't help much, as more corruption might have crept in after the last check.

[Jojo-Schmitz]

Done the "try by default"