Common action for setup ssh agent in GHA (#15902)

.github/workflows/upload_schema.yml

@@ -35,25 +35,9 @@ jobs:
         run: |
           echo "${{ secrets.GITHUB_TOKEN }}" | docker login ghcr.io -u ${{ github.actor }} --password-stdin
 
-      - name: Generate placeholder SSH private key if SSH auth for private repos is not needed
-        id: generate_key
-        shell: bash
-        run: |
-          if [[ -z "${{ secrets.PRIVATE_GITHUB_KEY }}" ]]; then
-            ssh-keygen -t ed25519 -C "github-actions" -N "" -f ~/.ssh/id_ed25519
-            echo "SSH_PRIVATE_KEY<<EOF" >> $GITHUB_OUTPUT
-            cat ~/.ssh/id_ed25519 >> $GITHUB_OUTPUT
-            echo "EOF" >> $GITHUB_OUTPUT
-          else
-            echo "SSH_PRIVATE_KEY<<EOF" >> $GITHUB_OUTPUT
-            echo "${{ secrets.PRIVATE_GITHUB_KEY }}" >> $GITHUB_OUTPUT
-            echo "EOF" >> $GITHUB_OUTPUT
-          fi
-
-      - name: Add private GitHub key to SSH agent
-        uses: webfactory/ssh-agent@v0.9.0
+      - uses: ./.github/actions/setup-ssh-agent
         with:
-          ssh-private-key: ${{ steps.generate_key.outputs.SSH_PRIVATE_KEY }}
+          ssh-private-key: ${{ secrets.PRIVATE_GITHUB_KEY }}
 
       - name: Pre-pull image to warm build cache
         run: |