Tests - Wait for elements before withdrawing their values

What does this MR do and why?

This MR adds waits for elements on product analytics dashboards before performing verifications.

This is needed to fix flaky Product Analytics tests. The tests intermittently fail when product analytics dashboard values are being withdrawn for verification.

Example of failure that this MR aims to fix: https://gitlab.com/gitlab-org/analytics-section/product-analytics/product-analytics-devkit-mirror/-/jobs/7837603190

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

N/A. Only test fix.

How to set up and validate locally

The tests can be executed locally by following this instructions.