chore: corrected IF statement for conversation GitHub Action (Unity-Technologies#3379)

This is a quick PR to correct IF statement in our github action because
with current state it was called (and failed) when PR was commented

Author: michalChrobot

.github/workflows/conversation-labels.yaml

@@ -21,7 +21,7 @@ env:
 jobs:
   conversation_labels:
     name: Calculate and update conversation labels of the issue
-    if: ${{ !github.event.issue.pull_request  }} && ${{ github.event.issue.state == 'open' }}
+    if: ${{ !github.event.issue.pull_request && github.event.issue.state == 'open' }}
     runs-on: ubuntu-latest
     permissions:
       issues: write