In MDL-64993 some changes were done in the data generators to add the self-conversation by default to all the users because firstly all users were supposed to have it created by default. However, in MDL-65566 some changes were done to improve the performance and finally, the self-conversation won't be created by default to all the new users (will be lazy-created when their conversations will be requested).

We need to remove the self-conversation from the data generators (and also the tests reviewed to consider the new self-conversation).

Note: Looking for "Remove the self conversations created by the generator" in tests will show you the places where we are assuming they exist.