[fix] Fixed excessive RAM usage and freezing when viewing tracks in Zune shell.

[amaid]

Overview

Closes #227

This fixes the memory allocation due to redundant(n^2) event attachment to ArtistItemsChange event in ZuneTrackCollectionItem for each artists on tracks. The event subscription has been moved from the collection item into the collection to avoid excessive memory allocation.

Checklist

This PR meets the following requirements:

• [x] Tested and contains NO breaking changes or known regressions.
• [x] Tested with the upstream branch merged in.
• [x] Tests have been added for bug fixes / features (or this option is not applicable)
• [x] All new code has been documented (or this option is not applicable)
• [x] Headers have been added to all new source files (or this option is not applicable)

Additional info

Not provided

[amaid]

Wasn't able to fully test. I keep getting a crash now when loading the Zune shell. Sandbox shell is fine. Will try again later.

In the end it turned out that the issue is unrelated to this PR but a general issue on the master branch, a new issue has been opened for this:

https://github.com/Arlodotexe/strix-music/issues/231