Fix private key reference in labeler.yml (#21153)

Updated the private key secret reference in the labeler workflow.

Author: Kyle-Neale

.github/workflows/labeler.yml

@@ -18,4 +18,4 @@ jobs:
     uses: ./.github/workflows/labeler-reusable.yml
     secrets:
       app-id: "${{ secrets.DD_AGENT_INTEGRATIONS_BOT_APP_ID }}"
-      private-key: "${{ secrets.DD_AGENT_INTEGRATIONS_BOT_PRIVATE_KEY_2 }}"
+      private-key: "${{ secrets.DD_AGENT_INTEGRATIONS_BOT_PRIVATE_KEY }}"