test(app-check, web): move to its own job to stop throttling of other e2e tests #5450

Job	Run time
android (tests)	7m 32s
ios (tests)	17m 31s
web (tests)	6m 17s
android (packages/cloud_firestore/cloud_firestore/example)	7m 2s
macos (tests)	8m 34s
ios (packages/cloud_firestore/cloud_firestore/example)	48m 26s
web (packages/cloud_firestore/cloud_firestore/example)	5m 20s
macos (packages/cloud_firestore/cloud_firestore/example)	5m 55s
web-app-check	4m 52s
web-wasm (tests)	3m 1s
windows	10m 50s
windows-firestore	8m 25s
web-wasm (packages/cloud_firestore/cloud_firestore/example)	6m 22s
	2h 20m 7s

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