Handle not found user profile gracefully

Changes from throwing an exception when a user profile is not found to returning null.

This prevents the application from crashing when a user profile is not found, allowing for more graceful error handling.

DrinkRateAPI/Services/ApplicationUserService.cs

@@ -13,7 +13,7 @@ public class ApplicationUserService(ApplicationDbContext context)
     {
         var appUserId = identity.FindFirst(ClaimTypes.NameIdentifier)?.Value;
         var profile = await _context.UserProfiles
-            .FirstAsync(x => x.ApplicationUserId.ToString() == appUserId)
+            .FirstOrDefaultAsync(x => x.ApplicationUserId.ToString() == appUserId)
             ?? throw new NotFoundException();
 
         return profile;