Fix/cypress resizeobserver mock

[AarishMansur]

Problem

Cypress tests trigger the browser error:

ResizeObserver loop completed with undelivered notifications

This happens when components using ResizeObserver cause repeated resize cycles in the Cypress environment.

The current workaround suppresses this error using Cypress.on('uncaught:exception'). While this prevents test failures, it hides real issues and reduces the reliability of the test suite.

Solution

Replaced the error suppression workaround with a proper ResizeObserver mock.

• Added a dedicated ResizeObserverMock utility that:

  • Implements the full ResizeObserver interface (observe, unobserve, disconnect)
  • Triggers callbacks asynchronously using requestAnimationFrame to avoid loops
  • Provides realistic contentRect values via getBoundingClientRect
  • Responds to window resize events to support responsive components

• Injected the mock using Cypress.on('window:before:load') so it is available before the application initializes

• Removed the uncaught:exception handler that was previously ignoring the error

• Updated Cypress TypeScript configuration to properly support .js files and prevent emit conflicts

This ensures stable test execution while keeping error reporting accurate.

How To Test

1. Run Cypress tests:

   yarn cypress run --spec cypress/e2e/list.cy.js

2. Verify:

• All tests pass successfully
• No ResizeObserver loop completed... errors appear
• No uncaught:exception suppression is present

Additional Checks

• The PR targets master for a bugfix or a documentation fix, or next for a feature
• The PR includes unit tests (not applicable this change affects test infrastructure only)
• The PR includes one or several stories (not applicable no UI changes)
• The documentation is up to date

Fixes : #10649