Only enable testplan item validator on issues with testplan item labels

.github/workflows/test-plan-item-validator.yml

@@ -8,11 +8,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Actions
+        if: contains(github.event.issue.labels.*.name, 'testplan-item') || contains(github.event.issue.labels.*.name, 'invalid-testplan-item')
         uses: actions/checkout@v2
         with:
           repository: 'JacksonKearl/vscode-triage-github-actions'
           ref: v19
       - name: Run Test Plan Item Validator
+        if: contains(github.event.issue.labels.*.name, 'testplan-item') || contains(github.event.issue.labels.*.name, 'invalid-testplan-item')
         uses: ./test-plan-item-validator
         with:
           label: testplan-item