feat(auth-service): get_names_with_email endpoint

[evanhutnik]

Summary

Adding new endpoint to auth service, POST /users/get_names_with_emails.

Similar to the existing POST /users/get_names endpoint, this one queries for the names for user_ids passed to it. The difference is if the user has not joined Macro or set a name in Macro, it falls back to checking for a name from the user's email contacts.

I added this as a separate endpoint, as the existing /get_names endpoint doesn't require authentication, but this one does (as we are using the authenticated user's email contacts). Also, there are use cases where we ONLY want the names from the Macro users. For example, the Get Channels endpoint uses /get_names to get the names for participants of a Macro channel. We don't want to include email contact names in this case as it would result in a mismatch between what that endpoint would return and what they would see when actually interacting with the user in Macro.

Email names are a single name column, so we do a (Peter approved) best-effort approach for splitting into first and last name, where we set first_name to the first word in the contact name, and last_name to the rest of it.

Screenshots, GIFs, and Videos

[linear]

BAC-138 Update user preview call in auth service to coalesce on email contact name

[whutchinson98]

missing 400 for user ids being empty