Adds tests for \MediaWiki\CommentFormatter\CommentItem
The test suite includes the following validations:
- Constructor initialization with expected parameters and behaviors.
- Checks correct assignment of LinkTarget objects.
- Assesses boolean flag manipulation for the same-page context.
- Examines wikiId setter with diverse input types.
Change-Id: Ibc12cced8da70cdf75bb1764ad16ce5dd872820b
