[Synthetics] Add note on timeout limits (#3962)

Closes #2411 and adds a note to the synthetics docs that timeouts have a
limit of 15 minutes. Please review and the note for alignment with the
corresponding [knowledge
article](https://support.elastic.dev/knowledge/view/10c028e4).

Author: mdbirnstiehl

solutions/observability/synthetics/configure-projects.md

@@ -171,6 +171,11 @@ Playwright has two types of timeouts that are used in Elastic Synthetics: [actio
 
 Elastic Synthetics uses a default action and navigation timeout of 50 seconds. You can override this default using [`actionTimeout`](https://playwright.dev/docs/api/class-testoptions#test-options-action-timeout) and [`navigationTimeout`](https://playwright.dev/docs/api/class-testoptions#test-options-navigation-timeout) in `playwrightOptions`.
 
+:::{note}
+Browser-based journeys have a timeout limit of 15 minutes.
+When `retry` is enabled (enabled by default), the journey attempts a second run if the first run times out. This allows for a maximum total runtime of 30 minutes: 15 minutes for the first run and up to 15 minutes for the retry.
+:::
+
 ### Timezones and locales [synthetics-configuration-playwright-options-timezones]
 
 The Elastic global managed testing infrastructure does not currently set the timezone. For {{private-location}}s, the monitors will use the timezone of the host machine running the {{agent}}. This is not always desirable if you want to test how a web application behaves across different timezones. To specify what timezone to use when the monitor runs, you can use `playwrightOptions` on a per monitor or global basis.