Expanded the test suite for `removeDownloadItem` in `src/__tests__/unit/downloadStatus.test.ts` to include:
- Removing multiple items with the same pkgname.
- Handling non-matching and non-existent pkgnames.
- Removing from an empty list.
- Ensuring exact string matching.
- Removing items from the start, middle, and end of the list.
Introduced a `createMockDownload` helper to reduce boilerplate in tests.
Co-authored-by: vmomenv <51269338+vmomenv@users.noreply.github.com>