fix: Create redis by default in public dns with cloud dns example

[levinandrew]

after terraform apply succeeded... wandb-app kept failing with the following at commit hash 00fefa79c305004a1dda3470bf58950e35b5df98

panic: dial tcp 10.152.243.127:0: i/o timeout

goroutine 1 [running]:
github.com/wandb/core/services/gorilla/cmd.RequiredCache(...)
	/home/circleci/go/src/github.com/wandb/core/services/gorilla/cmd/setup.go:1485
github.com/wandb/core/services/gorilla/cmd.(*gorillaCommander).MainCmd(0xc0014c0c00, {0xc0014c0d00, 0x1, 0x1})
	/home/circleci/go/src/github.com/wandb/core/services/gorilla/cmd/gorilla.go:656 +0xca05
main.main()
	/home/circleci/go/src/github.com/wandb/core/services/gorilla/cmd/megabinary/main.go:77 +0x431

the cacheConfig env var (passed into the the function call that returns the error that we panic with) was set to redis://wandb-redis-master:0?ttlInSeconds=60480

which got resolved to

wandb@wandb-app-76bd48749-rx6lz:~$ getent hosts wandb-redis-master
10.152.243.127  wandb-redis-master.default.svc.cluster.local

after setting that create_redis to true, wandb-app could start up successfully