chore: use code snippet for signal debugging

Signed-off-by: Heikki Hellgren <heikki.hellgren@op.fi>

plugins/notifications-backend/src/service/router.ts

@@ -470,7 +470,7 @@ export async function createRouter(
 
       if (!recipients || !title) {
         logger.error(`Invalid notification request received`);
-        throw new InputError();
+        throw new InputError(`Invalid notification request received`);
       }
 
       const origin = credentials.principal.subject;
@@ -496,8 +496,10 @@ export async function createRouter(
         try {
           users = await getUsersForEntityRef(entityRef);
         } catch (e) {
-          throw new InputError();
+          logger.error(`Failed to resolve notification receivers: ${e}`);
+          throw new InputError('Failed to resolve notification receivers', e);
         }
+
         const userNotifications = await sendUserNotifications(
           baseNotification,
           users,