Fix Instrument change text should show full instrument name

[CubikingChill]

Resolves: #32588 #23018

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[CubikingChill]

It appears that the value "TrackName" is used extensively, from mixer track name to "select instrument" page and "change instrument" in the score. Although the instrument name in these places should ideally be the same, it appears that they are not. Variant by key is specified in "select instrument" page but not the other 2. Seems we have to fix it by either specifying variant by key in all 3 fields, or simply use longName instead.

Eitherway, this has been vary confusing.

[shoogle]

This isn't the right solution. See #32511 (comment) for an explanation.

Instead, #32588 has the real issue and solution, which is to set instrument change text based on the output of formatInstrumentTitleOnScore().

[CubikingChill]

I will let you know when I come up with the fixed code.

[CubikingChill]

Can we reopen this PR?

[shoogle]

It's better to try a new solution in a fresh PR so it's not full of messages that are no longer relevant.

Also, it means we can keep this one as a record in case someone else considers trying the same solution in the future.

If you create a new PR for this issue, you can post a link to it here for the sake of people following along.