chore: Update eslint to use TS source flag
Description
This MR is a clone of chore: Update eslint to use TS source flag (!254 - merged) since that MR was accidentally merged into a non main branch. I had meant to block that MR from being merged until the parent one was in main. Now the parent one is merged, so I'm resurrecting this one.
From the commit:
- This fixes issue with oauth_callback flagging no-floating-promises error if TS is built but not showing error on a clean project
- https://github.com/typescript-eslint/typescript-eslint/issues/2094
(cherry picked from commit 89d62444)