Remove `referrerPolicy` from Cloudflare Worker `fetch` requests #12773

Job	Run time
Build Firestore	9m 21s
Test Firestore Compatible	5m 14s
Test Firestore Compatible on Firefox	6m 45s
Test Firestore on Firefox (test:browser)	10m 13s
Test Firestore (test:browser)	10m 49s
Test Nightly Firestore with Chrome	0s
Test Firestore on Firefox (test:travis)	4m 29s
Test Firestore (test:travis)	3m 49s
Test Firestore on Firefox (test:lite:browser)	1m 53s
Test Firestore (test:lite:browser)	1m 50s
Test Firestore on Firefox (test:browser:prod:nameddb)	10m 10s
Test Firestore (test:browser:prod:nameddb)	9m 17s
Test Firestore (test:lite:browser:nameddb)	1m 47s
Test Firestore on Firefox (test:lite:browser:nameddb)	1m 56s
Check all required tests results	1s
	1h 17m 34s

Provide feedback