[MM-54749] Make connectivity check more resilient to errors

[streamer45]

Summary

PR does a couple of things:

• Reworks the initial connectivity check polling so that it's more resilient to one off errors.
  • Before it was coupled in the same chromedp.Run command which meant that a single random network failure would cause the whole thing to fail. Now we continuously attempt until we reach the timeout regardless of errors which we simply log.
• Posting an explicit status update for when the recording is actually starting.
  • This will replace the proposed ws event in [MM-53432] Improve recording start time accuracy #44. I'll reconciliate that and related PRs at a later point after release.
  • This requires new changes in mattermost/mattermost-plugin-calls@1b8a805 to work.

Ticket Link

https://mattermost.atlassian.net/browse/MM-54749

[cpoile]

Much nicer, great!