Next Steps: Basic E2E coverage

eg: starting, closing, reopening tour.

### Testing concerns and catching regressions.

* E2Es may be the only level of testing able to verify the integration of this feature with the editor. However, due to the open source nature of the editor being beyond our control, past attempts at E2Es have created large maintenance burdens just in the tests themselves. More often E2Es fail as a problem in the test itself after a Gutenberg upgrade than because of an actual issue with the item they are testing. Given this, it may be best to avoid comprehensive E2Es and focus only on a few key checks.
* An addition we should supply is well documented and communicated testing flows to happen during Gutenberg upgrades, as well as monitoring influx of tracking events related to TourKit failures listed above (final safety net).

Review the proposed E2E flows for starting, closing, and reopening the tour, along with the testing concerns around Gutenberg upgrades and TourKit failures. Identify the few key integration checks worth maintaining and define the documented upgrade-testing and monitoring flows; the issue is complete when those next steps are agreed and specified.

Written by the indexing model from the issue text.