fix(release): prevent validation error in patch-from-comment workflow (google-gemini#8759)

Author: SandyTao520

.github/workflows/release-patch-from-comment.yml

@@ -55,7 +55,7 @@ jobs:
         uses: 'actions/github-script@00f12e3e20659f42342b1c0226afda7f7c042325'
         with:
           script: |
-            const args = ${{ fromJSON(steps.slash_command.outputs.command-arguments) }};
+            const args = ${{ fromJSON(steps.slash_command.outputs.command-arguments || '{}') }};
             github.rest.actions.createWorkflowDispatch({
               owner: context.repo.owner,
               repo: context.repo.repo,