Fix: allow release-assets.githubusercontent.com in AI docs workflow (#3290)

GitHub now redirects release asset downloads to
release-assets.githubusercontent.com, which was blocked by
harden-runner's egress policy, causing cosign install to fail with curl
exit code 6 (could not resolve host).

This fixes that issue.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: matthewhelmke

.github/workflows/compile-ai-docs-from-gcs.yaml

@@ -45,6 +45,7 @@ jobs:
           iamcredentials.googleapis.com:443
           oauth2.googleapis.com:443
           objects.githubusercontent.com:443
+          release-assets.githubusercontent.com:443
           pypi.org:443
           raw.githubusercontent.com:443
           rekor.sigstore.dev:443