Separate UI Tests from E2E Test Suite

[pedro-stanaka]

Summary:
Currently, UI tests using Chrome are integrated with our E2E test suite, causing flakiness and performance issues. This issue proposes separating these UI tests into a dedicated test suite to improve overall test stability and maintainability.

Background:

• Current E2E tests use chromedp for network request checks and UI testing.
• These tests are experiencing flakiness, especially on the main branch.
• The use of a full browser for these tests is causing performance issues in CI.

Objectives:

1. Separate Chrome-based UI tests from the main E2E test suite.
2. Improve test stability and reduce flakiness.
3. Optimize CI performance by isolating resource-intensive browser tests.

Proposed Changes:

1. Create a new dedicated UI test suite.
2. Move all Chrome-based tests from the E2E suite to the new UI suite.
3. Update CI pipeline to run UI tests separately from other E2E tests.
4. Implement headless browser testing for improved performance (as suggested in PR Fixing E2E tests using headless Chrome #8005).

See slack thread: https://cloud-native.slack.com/archives/CL25937SP/p1734412998861709