Remove unused mock_traces

What does this MR do and why?

This MR is a follow-up to !133008 (merged)

Upon revisiting the previous MR, it became apparent that the mock file referenced in that MR is not being imported anywhere within the project. Despite its absence, the pipeline continues to pass without any issues. Therefore, this MR aims to remove the unused mock file from the codebase.

Screenshots or screen recordings

No visual changes.

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