[keyserver] Also delete from ids table when deleting invite links
Summary: Noticed this query wasn't deleting from the ids table. Turns out that the RETURNING keyword isn't allowed for multi-table deletes, so I had to rework the logic.
Test Plan:
- I deleted an invite link from the UI and confirmed it was removed from MariaDB and DynamoDB
- I tested in combination with the next diff, where I introduce a cronjob for deleting orphaned invite links
Reviewers: tomek
Reviewed By: tomek
Differential Revision: https://phab.comm.dev/D13731