Remove timecop from Gemfile

What does this MR do and why?

This removes timecop from Gemfile as it’s no longer needed after these MRs are merged:

• !76030 (merged)
• !76031 (merged)
• !76032 (merged)
• !76033 (merged)
• !76034 (merged)

After this MR is merged, #214432 (closed) can be closed. 🎊

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