[🐴] Copy tweaks (#4042)

* `notifications` -> `conversation`

* `users` -> `people`

* `other participants` -> `the other participant`

* rename

src/components/dms/MessageMenu.tsx

@@ -119,7 +119,7 @@ export let MessageMenu = ({
         control={deleteControl}
         title={_(msg`Delete message`)}
         description={_(
-          msg`Are you sure you want to delete this message? The message will be deleted for you, but not for other participants.`,
+          msg`Are you sure you want to delete this message? The message will be deleted for you, but not for the other participant.`,
         )}
         confirmButtonCta={_(msg`Delete`)}
         confirmButtonColor="negative"