Wrap individual puppeteer navigations in try/catch block

[westonruter]

When running benchmark-web-vitals with high numbers (e.g. 250) I would eventually encounter errors like:

Network.enable timed out. Increase the 'protocolTimeout' setting in launch/connect calls for a higher timeout if needed.

or

Navigation timeout of 30000 ms exceeded.

or

Timed out after waiting 30000ms.

When these occur, the entire process quit early without completing all of the expected iterations over the URLs. I found that this was because there was a missing try/catch block around each individual iteration. This meant it would move on to process the next URL which is where the existing exception handling is located:

wpp-research/cli/commands/benchmark-web-vitals.mjs

Lines 385 to 393 in dca5646

	// Catch Puppeteer errors to prevent the process from getting stuck.
	try {
	const { completeRequests, metrics } = await benchmarkURL(
	url,
	browser,
	metricsDefinition,
	params,
	logIterationsProgress
	);

By adding this additional try/catch block, if there is a Puppeteer error, it will be the same as if the HTTP response returned with a failure. Such errors will then be reflected in the overall success rate.

Review this PR with whitespace changes ignored.