Update periodic connection check for accuracy

[aaemnnosttv]

Feature Description

In #9083 we updated the periodic connection check Site Kit performs which tests for internet connectivity by pinging our REST index endpoint. There is still the potential for inaccurate behavior in the event that the request fails – this happened for me recently when my session timed out and the request failed due to a bad REST nonce. Such a failure is irrelevant to this check though which is only concerned with the request connecting to the backend successfully, rather than authenticating, etc.

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Do not alter or remove anything below. The following sections will be managed by moderators only.

Acceptance criteria

• The internet connectivity check should only trigger the offline notification if the backend is unreachable

Implementation Brief

• Update the fetch made to use fetch rather than apiFetch (adapting as necessary) and remove checks on its response (if the call does not throw, consider online=true, otherwise catch and set false
  

  site-kit-wp/assets/js/hooks/useMonitorInternetConnection.js

  Lines 55 to 67 in 3a6fd17

  	try {
  	const connectionCheckResponse = await apiFetch( {
  	path: '/google-site-kit/v1/',
  	} );
  	// We are only interested if the request was successful, to
  	// confirm online status.
  	const canReachConnectionCheck = !! connectionCheckResponse;
  	setIsOnline( canReachConnectionCheck );
  	} catch ( err ) {
  	setIsOnline( false );
  	}

• api-fetch cannot be used because it will throw for any non 200-300 response

Test Coverage

• Update existing coverage as needed

QA Brief

Changelog entry