refactor+fix various issues with regs/logins and admin user commands

Signed-off-by: June Clementine Strawberry <june@3.dog>

src/service/appservice/mod.rs

@@ -90,7 +90,7 @@ impl Service {
 			.write()
 			.await
 			.remove(appservice_id)
-			.ok_or(err!("Appservice not found"))?;
+			.ok_or_else(|| err!("Appservice not found"))?;
 
 		// remove the appservice from the database
 		self.db.id_appserviceregistrations.del(appservice_id);