Investigate issues with Cy.viewport

## Summary
When running Cypress tests in Open Mode, it appears that Cy.viewport does not work consistently. Usually, there are no issues on the first run, but rerunning the tests causes changes in the viewport/ resulting snapshot. This causes the visual regression tests to fail until the Cypress UI is restarted.

## 💬 Description
This task is to investigate the issue and resolve so that Cypress tests pass consistently when run in Open Mode, without needing to restart the Cypress UI.

## Why do we need it?
It can be frustrating when running tests and cause users to think that there are issues with the components when the visual regression snapshots differences are not within the threshold.

Start by reproducing the viewport behavior in Cypress Open Mode using Cy.viewport, rerunning the visual regression tests and observing the resulting snapshots. Trace the relevant test setup and Cypress UI state until the cause is identified; done means repeated test runs produce consistent viewport dimensions and snapshots without restarting the Cypress UI.

Written by the indexing model from the issue text.