Syntax fixes (#5367)

* Declare return types on functions

And a very few other type related minor fixes

* Minor syntax fixes

* Remove unnecessary escape chars in regexes
* Remove unnecessary awaits
* Replace deprecated req.connection with req.socket
* Replace deprecated upload with uploadOne
* Remove unnecessary eslint-disable-next-line comments
* Comment empty functions / catch or finally clauses
* Fix irregular whitespaces
* Add missing returns (null)
* Remove unreachable code
* A few logical fixes
* Remove / Handle non-null assertions which are certainly unnecessary (e.g. in
tests)

api/src/controllers/auth.ts

@@ -311,7 +311,9 @@ router.get(
 		try {
 			const email = getEmailFromProfile(req.params.provider, req.session.grant.response?.profile);
 
-			req.session?.destroy(() => {});
+			req.session?.destroy(() => {
+				// Do nothing
+			});
 
 			authResponse = await authenticationService.authenticate({
 				email,