Enhance periodic connection check

[aaemnnosttv]

Feature Description

In #3820 we introduced infrastructure for informing the user when their network connection is lost including periodic checks to confirm.

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Acceptance criteria

• The periodic request to check connectivity should not be called immediately on page load (the page load itself is a signal of connectivity); the first request should happen either in response to a detected change in connectivity or it's normal 2 min interval
• The user's session expiring should not be treated as being offline

Implementation Brief

• [ ] Remove the checkInternetConnection call from the on mount lifecycle callback https://github.com/google/site-kit-wp/blob/c701f21e8c60bb9ad8a953ea9912523403b727d8/assets/js/hooks/useMonitorInternetConnection.js#L80
• [ ] Remove the connection-check endpoint definition
• [ ] Replace the connection-check request in useMonitorInternetConnection with a request to Site Kit's REST index: google-site-kit/v1/ which is publicly accessible so it won't fail if the user's session expires
  • Use wp.apiFetch({path: '/google-site-kit/v1/'})
  • Update assets/js/googlesitekit/api/index.js to expose apiFetch on its export rather than rely on external/shared version
  • The fetch will throw an error if fetch fails due to no connection with the familiar "You are probably offline" error
• [ ] Remove other references to connection-check such as in the list of excludedEndpoints

Test Coverage

• Update tests for the hook to reference the change of endpoint

QA Brief

• Set up Site Kit
• Use network tab of developer tools, or WiFi module, to switch offline
• Verify that offline notification is showing, and request to the /google-site-kit/v1/ endpoint is being made
• Verify that request to the above endpoint is not made on the page load
• Verify that switching back to online the notification disappears

Changelog entry

• Improve offline connection check logic/behaviour.

[eugene-manuilov]

IB ✔️

[wpdarren]

QA Update: ✅

Verified:

• Offline notification is showing, and request to the /google-site-kit/v1/ endpoint is being made
• The request to the above endpoint is not made on the page load
• Switching back to online the notification disappears.

Screenshots