If an instance is not set to integrate then skip the validation check against it.

This should fix the issue described [here](https://community.ynput.io/t/houdini-local-render-and-publish-existing-frames-error/2647/7?u=bigroy) where a matching "render instance" is generated for the local rendering spawning off from an initial instance - where the initial instance becomes set to not integrate (integrate=False) but remain available for further validations (publish=True).

client/ayon_core/plugins/publish/validate_unique_subsets.py

@@ -34,7 +34,11 @@ class ValidateProductUniqueness(pyblish.api.ContextPlugin):
         for instance in context:
 
             # Ignore disabled instances
-            if not instance.data.get('publish', True):
+            if not instance.data.get("publish", True):
+                continue
+
+            # Ignore disabled instances
+            if not instance.data.get("integrate", True):
                 continue
 
             # Ignore instance without folder data