Update browser support docs for INP and LCP

[Mimori256]

I've been using this library and do appreciate this project! While reading through the README, I noticed that Firefox isn't mentioned as a supported browser for onINP(), but according to this Mozilla blog post, Firefox 144+ (released October 2025) now supports PerformanceEventTiming.interactionId, which enables INP measurement.

web-vitals/src/onINP.ts

Lines 66 to 80 in 1b872cf

	export const onINP = (
	onReport: (metric: INPMetric) => void,
	opts: INPReportOpts = {},
	) => {
	// Return if the browser doesn't support all APIs needed to measure INP.
	if (
	!(
	globalThis.PerformanceEventTiming &&
	'interactionId' in PerformanceEventTiming.prototype
	)
	) {
	return;
	}
	const visibilityWatcher = getVisibilityWatcher();

↑interactionId is now supported so the INP measuremet is performed on Firefox 144+

To help avoid confusion for users, this PR updates the documentation to reflect Firefox 144+ support and removes an outdated comment in the test utilities.

I'd love to hear the thoughs on this change!

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[tunetheweb]

Thanks! Suggested some tweaks since Safari support is coming soon too.

[Mimori256]

Thanks for the feedback! I’ve addressed all the requested changes.

[tunetheweb]

LGTM. Thanks for this.