Potential circular import issue in SuggestionFilteringTool

[suhaibmujahid]

Potential circular import issue: this module imports GeneratedReviewComment from bugbug.tools.code_review.agent, while bugbug.tools.code_review.agent imports SuggestionFilteringTool from this module. This circular dependency could cause import errors. Consider moving GeneratedReviewComment to a shared data types module or using TYPE_CHECKING with forward references.

Originally posted by @Copilot in #5588 (comment)