More cosmos tests running against mock transport

[rylev]

This PR moves more tests over to running against the mock transport framework which means more of the cosmos DB operations will be tested in CI.

It also deletes a few tests which were testing the exact same things as other tests.

There are three tests in cosmos which have not yet been moved to the mock framework:

• Attachments: attachments are deprecated and my personal account does not have the feature meaning I can't run the tests.
• UDF: I'm getting an authorization error that I don't quite understand, and I need to do more investigation.
• permission_token_usage: I need to understand the code more deeply and potentially merge it with the permissions_operations test