TrfTestsART: Add Merge_tf test for AODs with MP, CA and SharedWriter

Johannes Elmsheuserrequested to merge
elmsheus/athena:trftestsart_20230606 into 23.0

This MR adds a Merge_tf ART test in the TrfTestsART package for AODs with MP, CA and SharedWriter mode. This is a follow-up to the discussion in ATEAM-910

Tagging @amete for info.

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