refactor: use OSS Pulsar image and charts for e2e tests

[mattsre]

This PR is stacked on #365 and should be rebased once that PR is merged

Motivation

CI runs on an ancient version of K8S and old versions of Pulsar. Newer versions of sn-platform images require a license key to run, so these cannot easily be bumped. The existing e2e tests rely on exec'ing into pods and running pulsarctl commands, but this binary is not in OSS Pulsar images which makes it difficult to test locally for OSS contributors looking to make changes to the project.

Modifications

• Update CI to run on k8s 1.34 and use OSS Pulsar 4.1 Docker images
• Update tests to work with OSS Pulsar images (no pulsarctl available in images)
• Fix some lint findings

Verifying this change

• Make sure that the change passes the CI checks.

This change is already covered by existing tests. CI upgrade was tested on a PR in my fork here: mattsre#1 as well as running locally

Documentation

• no-need-doc

Internal changes to CI and tests, no package changes