core(service-worker): remove service-worker gatherer

[adrianaixba]

continuation of the PWA category + unused gatherers removal: #15535

[adamraine]

Several other references I found:

lighthouse/core/test/scripts/run-mocha-tests.js

Line 73 in 79c78be

'core/test/gather/gatherers/service-worker-test.js',

lighthouse/core/test/runner-test.js

Lines 38 to 41 in 79c78be

	await td.replaceEsm('../gather/driver/service-workers.js', {
	getServiceWorkerVersions: jestMock.fn().mockResolvedValue({versions: []}),
	getServiceWorkerRegistrations: jestMock.fn().mockResolvedValue({registrations: []}),
	});

lighthouse/types/artifacts.d.ts

Lines 144 to 145 in 79c78be

	/** Version information for all ServiceWorkers active after the first page load. */
	ServiceWorker: {versions: Crdp.ServiceWorker.ServiceWorkerVersion[], registrations: Crdp.ServiceWorker.ServiceWorkerRegistration[]};