Improved e2e test reliability

[Sebastian-Webster]

With #4515 the tests passed locally, but ever since then some tests (mostly funnel/funnel, funnel/pyramid, and line/line-with-annotations) would sometimes fail spontaneously and running the tests again with no code changes would fix the error. Adding a while loop to wait for all timers/intervals/network requests and the chart animation to end fixes the reliability issues.
This change would also improve reliability for future possible tests, like for example if a test needed a timeout after the chart animation ended, the test would not wait for that timeout because it had already waited for all timeouts to finish. With this PR, if a timeout is created after a chart animation ends, the test would wait for the timeout to end before continuing.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes