feat(api): enhance logging for mobile login endpoint (#59159)

api/src/routes/public/auth.ts

@@ -43,13 +43,21 @@ export const mobileAuth0Routes: FastifyPluginCallback = (
   fastify.get('/mobile-login', async (req, reply) => {
     const email = await getEmailFromAuth0(req);
 
+    const logger = fastify.log.child({ req });
+
+    logger.info('Mobile app login attempt');
+
     if (!email) {
+      logger.error('Could not get email from Auth0 to log in');
+
       return reply.status(401).send({
         message: 'We could not log you in, please try again in a moment.',
         type: 'danger'
       });
     }
     if (!isEmail(email)) {
+      logger.error('Email is incorrectly formatted for login');
+
       return reply.status(400).send({
         message: 'The email is incorrectly formatted',
         type: 'danger'