Fixed many expression issues and improved the properties panel

[maiko3tattun]

Development Background:

When lyrics or color changes reduced the number of phonemes in a note, old expressions that were no longer needed could cause bugs (e.g. Japanese phonemizer does not work well).
So I have improved that when right clicking on the UI to delete an expression, unwanted expressions with the same abbr in the same note are deleted.

Feature Improvements:

• Remove expression when right-clicking combo box in properties panel - NotePropertyExpression.axaml/axaml.cs
• Changed to remove instead of set the value when the same value as the default value of track expression is selected in the properties panel - NotePropertiesViewModel

Fixes:

• Fixed Phonemizer not running immediately after selecting voice color in properties panel - ExpCommand
• Fixed a case where the expression of the first phoneme of the selected note should be displayed, but the one of the second or later phonemes was displayed - NotePropertiesViewModel
• When right-clicking on the UI to delete an expression, modified to delete unwanted expressions with the same abbr in the same note - UNote, UPhoneme

Note:

The default expressions for tracks have been implemented internally and are awaiting UI development.
In case the default values changed on a track-by-track in the future, I'm clearly separating the handling of cases where the default value is set and the value is null.