[SG-31710] Migrate E2E tests from mocha to jest

Created by: gitstart-sourcegraph

Implementation

1. Migrate all tests in client/web/src/end-to-end from Mocha to Jest
2. Migrate all tests in client/browser/src/end-to-end from Mocha to Jest
3. Ensure tests still run and pass as expected

SG Issue Gitstart Ticket

Test plan

• Check all files in client/web/src/end-to-end and client/web/src/end-to-end are migrated from Mocha to Jest.
• Check CI and ensure tests still run and pass as expected

Preview App

• Frontend
• storybook