Gracefully handle API 404 when no data present

[pdclark]

Possibly related: https://stackoverflow.com/questions/67503965/why-i-miss-some-data-on-querying-of-chrome-ux-report-api

When no data is present in the Chrome API, the API returns a 404.
This causes a 404 in the console, and no admin menu appears on the front-end.

Uncaught (in promise) Error: chrome ux report data not found
    at generateReport (script.js?ver=1.0:17)

const CrUXApiUtil = {};
CrUXApiUtil.KEY = wpWebVitals.cruxApiKey;

// Gather the data for example.com and display it
async function generateReport() {
	const endpointUrl = 'https://chromeuxreport.googleapis.com/v1/records:queryRecord';
	const resp = await fetch( `${endpointUrl}?key=${CrUXApiUtil.KEY}`, {
		method: 'POST',
		body: JSON.stringify( {
			origin: window.location.href
		} ),
	} );

	const json = await resp.json();

	if (!resp.ok) {
➡️		throw new Error( json.error.message );
	}

Expected results:

The menu should display with some error message letting the user know that no data was returned from the API and to please wait (or do whatever else it takes to resolve the issue.)