[ZEPPELIN-6358] Seperate environment config and shared utilities from #5101

[dididy]

What is this PR for?

In #5101, the amount of changes became too large, and a committer suggested splitting it into smaller parts. Since the updates related to the common test environment and shared utility functions have already proven to be stable, I separated those pieces into this dedicated PR.

This PR includes only the safe, standalone changes that improve the shared E2E environment and utilities.

[Summary of Changes]

• Refined and separated E2E test environment setup

  • Improved global setup/teardown

    • CI: using ZEPPELIN_E2E_TEST_NOTEBOOK_DIR
    • To use ZEPPELIN_E2E_TEST_NOTEBOOK_DIR locally, the server has to be restarted at least once, which feels a bit odd to enforce during E2E test execution. To make things less messy from a UI perspective, I reorganized the structure so that all tests are collected under E2E_TEST_FOLDER instead.

  • Added folder/notebook initialization and cleanup logic

    • you can run it standalone with this command:npm run e2e:cleanup(automatically run this once the tests are finished)

• Extracted shared utilities and constants

  • Added common E2E constant (e.g., E2E_TEST_FOLDER)
  • Introduced cleanup utilities to ensure stable post-test state

• Updated GitHub Actions (frontend.yml)

  • Added environment variables(for python interpreter), notebook repo initialization, and cleanup steps
  • Due to potential storage and cost concerns, I shortened the retention period for the Playwright report from 30 days to 3 days

• Updated Playwright / ESLint configurations

  • ts to cjs

What type of PR is it?

Improvement Refactoring

Todos

What is the Jira issue?

ZEPPELIN-6358

How should this be tested?

cd zeppelin-web-angular
nvm use
npm run start
npm run e2e
npm run e2e:cleanup

Screenshots (if appropriate)

Questions:

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