Only attempt to decrypt if we have encrypted in the build step

Change-type: patch
Signed-off-by: Ryan Cooke<[email protected]>

.github/workflows/yocto-build-deploy.yml

@@ -1138,6 +1138,9 @@ jobs:
           path: ${{ env.WORKSPACE }}
 
       - name: Decrypt artifacts
+        if: |
+          github.event.repository.private != true &&
+          (inputs.sign-image == true || needs.build.outputs.is_private == 'true')
         working-directory: ${{ env.WORKSPACE }}
         run: |
           for artifact in *.enc **/*.enc; do