Fix op-rbuilder release action (flashbots#541)

## 📝 Summary

We removed optimism feature flag, fixing it in the action
## 💡 Motivation and Context

<!--- (Optional) Why is this change required? What problem does it
solve? Remove this section if not applicable. -->

---

## ✅ I have completed the following steps:

* [ ] Run `make lint`
* [ ] Run `make test`
* [ ] Added tests (if applicable)

Author: SozinM

.github/workflows/release-op.yaml

@@ -77,7 +77,7 @@ jobs:
           # - target: aarch64-apple-darwin
           #   runner: warp-macos-14-arm64-6x
         features:
-          - ${{ github.event.inputs.features }}${{ github.event.inputs.features && ',' }}optimism
+          - ${{ github.event.inputs.features || '' }}
 
     steps:
       - name: Install dependencies
@@ -162,7 +162,7 @@ jobs:
     strategy:
       matrix:
         features:
-          - ${{ github.event.inputs.features }}${{ github.event.inputs.features && ',' }}optimism
+          - ${{ github.event.inputs.features || '' }}
     steps:
       - name: checkout sources
         uses: actions/checkout@v4