Change self-hosted runner label to extra-c20m50

Updated runner label from huge-c10m25 to extra-c20m50 for benchmarks.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: mwiewior

.github/workflows/benchmark.yml

@@ -21,7 +21,7 @@ on:
 
 jobs:
   benchmark:
-    runs-on: [self-hosted, huge-c10m25]
+    runs-on: [self-hosted, extra-c20m50]
     permissions:
       contents: write
       pull-requests: write