ci: bump ci builder 0.50.0

Bumps the `ci-builder` image with an updated version
of foundry.

Foundry update:
#11325

Docker build:
https://app.circleci.com/pipelines/github/ethereum-optimism/optimism/60263/workflows/154fd94a-4029-4e2f-8bce-4ea4c6d25897

.circleci/config.yml

@@ -3,7 +3,7 @@ version: 2.1
 parameters:
   ci_builder_image:
     type: string
-    default: us-docker.pkg.dev/oplabs-tools-artifacts/images/ci-builder:v0.49.0
+    default: us-docker.pkg.dev/oplabs-tools-artifacts/images/ci-builder:v0.50.0
   ci_builder_rust_image:
     type: string
     default: us-docker.pkg.dev/oplabs-tools-artifacts/images/ci-builder-rust:latest