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

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

apps/account/serializers/user.py

@@ -41,8 +41,8 @@ class UserProfileSerializer(serializers.ModelSerializer):
 
 
 class UserRegisterSerializer(serializers.ModelSerializer):
-    fcm = serializers.CharField(required=False)
-    device_id = serializers.CharField(required=False)
+    fcm = serializers.CharField(required=False, allow_blank=True, allow_null=True)
+    device_id = serializers.CharField(required=False, allow_blank=True, allow_null=True)
     email = serializers.EmailField()
       
     class Meta: