Fix multiple clarinets sharing the same name in score.

[CubikingChill]

Resolves: #32511 #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.