deploy-nightly.yml: Release number is not provieded (#738)

Remove unused: `Set environment variables` Step on deploy-nightly CI

.github/workflows/deploy-nightly.yml

@@ -30,9 +30,6 @@ jobs:
         username: ${{ github.actor }}
         password: ${{ secrets.GITHUB_TOKEN }}
 
-    - name: Set environment variables
-      run: echo RELEASE=$(cat ./src/package.json | jq -r .release) >> $GITHUB_ENV
-
     - name: Build & Publish Docker Image
       uses: docker/build-push-action@v5
       with: