fix: skip regression analysis comment for Dependabot PRs

- Add 'if: github.actor != dependabot[bot]' to Comment Regression Analysis step
- Fixes 'Resource not accessible by integration' error on Dependabot PRs
- Benchmarks are working correctly (3% change, no regression)
- Only the comment step fails due to Dependabot token restrictions

Author: avrabe

.github/workflows/performance.yml

@@ -509,6 +509,7 @@ jobs:
         fi
 
     - name: Comment Regression Analysis
+      if: github.actor != 'dependabot[bot]'
       uses: actions/github-script@v8
       with:
         script: |