[ZEPPELIN-6698] Verify EventBus note-removal browser parity

[voidmatcha]

What is this PR for?

Verify that Job Manager receives the same note removal WebSocket payload in legacy and EventBus server modes.

This draft contains the ZEPPELIN-6340 server commit from PR #5441 because that prerequisite is not on master. After #5441 merges, this branch will be rebased so the final PR contains only the browser parity test and CI matrix.

What type of PR is it?

Improvement

Todos

• Add browser coverage for both server modes
• Add the EventBus frontend CI matrix
• Rebase after PR [ZEPPELIN-6340] Add ZeppelinEventBus and update NotebookServer to handle NoteRemoveEvent #5441 merges

What is the Jira issue?

ZEPPELIN-6698

How should this be tested?

cd zeppelin-web-angular
CI=true PLAYWRIGHT_HTML_OPEN=never ./node/npm run e2e -- --reporter=list tests/workspace/job-manager/eventbus-removal-parity.spec.ts
./node_modules/.bin/eslint e2e/tests/workspace/job-manager/eventbus-removal-parity.spec.ts
./node/npm exec prettier -- --check e2e/tests/workspace/job-manager/eventbus-removal-parity.spec.ts
cd ..
./mvnw test -pl zeppelin-server -Dtest=ZeppelinEventBusTest,NotebookServerTest#testEventBusHandlesNoteRemovedEvent -DfailIfNoTests=false

Screenshots (if appropriate)

Not applicable.

Questions:

• Does the license files need to update? No
• Is there breaking changes for older versions? No
• Does this needs documentation? No