Hyperlink from "Connection Error" screen to Troubleshooting article

[philrz]

Recently we experienced the second incident of a community user bumping into the "Connection Error: The service at localhost:9867" symptom detailed at #1490. Unsurprisingly, for both users we know of that have hit this issue, they ultimately end up coming to public Slack for help. Now that this has happened a couple times, we've got an article on the Brim wiki that would hopefully help a user start troubleshooting the problem immediately rather than having to take the detour to Slack and wait for a response:

https://github.com/brimsec/brim/wiki/Troubleshooting#brim-shows-connection-error-the-service-at-localhost9867-could-not-be-reached

In a group discussion on March 2, 2021, there was consensus that we could add a hyperlink from the "Connection Error" screen directly to the troubleshooting article. Proposed text attached to the hyperlink (with the link attached to the text that's in bold):

Please see the Brim troubleshooting wiki for guidance to debug/resolve this issue

[philrz]

Verified in Zui commit a1cc8fc.

The attached video shows the new Connection Error screen in the two locations that formerly lacked a hyperlink to the docs.

Verify.mp4

While verifying, I happened to notice a small loose end related to this which is tracked in new issue #2731.