test(e2e): remove stale policy retries

[TaylorMutch]

Summary

Remove the expected-allowed HTTP 403 retries that masked the startup stale-policy race. The affected E2E scenarios now make one request and will fail if proxy readiness regresses.

Related Issue

Closes #1942

Changes

• make the REST L7 allowed request a single attempt
• make all GraphQL forward-proxy allowed requests single attempts
• retain the separate raw-socket transport retry for connection startup

Testing

• Checks appropriate to the affected code and behavior pass
• Unit tests added/updated (if applicable)
• E2E tests added/updated (if applicable)

Focused Docker E2E run:

forward_proxy_graphql_l7: 1 passed
forward_proxy_l7_bypass: 2 passed

Also passed cargo fmt --manifest-path e2e/rust/Cargo.toml --all -- --check and git diff --check.

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)
• Architecture docs updated (if applicable)