github_webhook: Fix create of new hook with existing hooks (#54458)

When creating a new webhook with existing hooks already in place, the
module would erroneously select one of the existing hooks to update
instead of creating the hook anew. This fixes that bug.

lib/ansible/modules/source_control/github_webhook.py

@@ -255,6 +255,8 @@ def main():
         for hook in repo.get_hooks():
             if hook.config.get("url") == module.params["url"]:
                 break
+        else:
+            hook = None
     except github.GithubException as err:
         module.fail_json(msg="Unable to get hooks from repository %s: %s" % (
             module.params["repository"], to_native(err)))