[Bug]: Left frame no longer showing in Javadoc

### What happened?

In the Javadoc, the left frame is no longer appearing on the left side of the screen. It's making Javadoc very difficult to use.

Frame in 2.66.0 https://beam.apache.org/releases/javadoc/2.66.0/
No frame in 2.67.0 https://beam.apache.org/releases/javadoc/2.67.0/

### Issue Priority

Priority: 3 (minor)

### Issue Components

- [ ] Component: Python SDK
- [x] Component: Java SDK
- [ ] Component: Go SDK
- [ ] Component: Typescript SDK
- [ ] Component: IO connector
- [ ] Component: Beam YAML
- [ ] Component: Beam examples
- [ ] Component: Beam playground
- [ ] Component: Beam katas
- [ ] Component: Website
- [ ] Component: Infrastructure
- [ ] Component: Spark Runner
- [ ] Component: Flink Runner
- [ ] Component: Prism Runner
- [ ] Component: Twister2 Runner
- [ ] Component: Hazelcast Jet Runner
- [ ] Component: Google Cloud Dataflow Runner