Fix pulp_container_content when allow_missing is false

Without this we see the following error if allow_missing is false and a
tag does not exist in the source repository:

  unhashable type: 'dict'

This change fixes the issue by pulling the tag names out of the Pulp API
response.

Author: markgoddard

plugins/modules/pulp_container_content.py

@@ -136,10 +136,11 @@ def get_content_units(self, repo):
             tags.extend(search_result["results"])
             offset += PAGE_LIMIT
 
+        tag_names = [tag["name"] for tag in tags]
         if (self.module.params["state"] == "present" and
                 not self.module.params["allow_missing"] and
-                len(tags) != len(self.module.params["tags"])):
-            missing = ", ".join(set(self.module.params["tags"]) - set(tags))
+                len(tag_names) != len(self.module.params["tags"])):
+            missing = ", ".join(set(self.module.params["tags"]) - set(tag_names))
             raise SqueezerException(f"Some tags not found in source repository: {missing}")
         return [result["pulp_href"] for result in tags]