Upgrade prod mongo from v5 to v6
This is needed for `$in` function in TTL index: https://github.com/huggingface/datasets-server/pull/1325/files#diff-44fa7cb2645881e55953db64dafa198b2e007a2e531f70acaeebfc50ffa67953R141

See https://www.mongodb.com/docs/manual/release-notes/6.0/#indexes

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to upgrade: https://www.mongodb.com/docs/atlas/tutorial/major-version-change/
Upgrade prod mongo from v5 to v6: This is needed for `$in` function in TTL index: https://github.com/huggingface/datasets-server/pull/1325/files#diff-44fa7cb2645881e55953db64dafa198b2e007a2e531f70acaeebfc50ffa67953R141

See https://www.mongodb.com/docs/manual/release-notes/6.0/#indexes

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to upgrade: https://www.mongodb.com/docs/atlas/tutorial/major-version-change/