fix(account): allow blank and null values for fcm and device_id in user registration

- Updated fcm and device_id fields in UserRegisterSerializer to allow blank and null values, enhancing flexibility in user registration.

apps/account/serializers/user.py

@@ -51,7 +51,6 @@ class UserRegisterSerializer(serializers.ModelSerializer):
         extra_kwargs = {
             'fullname': {'required': True,},
             'email': {'required': True,},
-            'device_id': {'required': False,},
         }
 
     def validate_email(self, value):