Write documentation that allows frontend engineers to contribute to frontend observability

Depending on how we decide to track frontend errors, we'll need to write a documentation update to ensure our frontend engineers can contribute effectively.

This could include:

• Which errors we should report to Sentry explicitly and which should be only shown to users (e.g. as alerts)
• How to catch errors correctly so sentry can display them reliably.
• How to catch special cases you want to track (like we did with the pipeline graph)
• How to navigate sentry and find errors
• How to debug sentry errors effectively

MR: Expand Sentry docs page in the frontend guide (!133203 - merged)