test(storage): increase timeout for ACL test retry (#6618)

Previously the docs said that these operations would take effect
within 10s, but I noticed that at some point this was loosened
up to "at least 30s" and "about a minute" depending on the
location. I think these tests will still usually run in a similar
amount of time, but hopefully extending this timeout will avoid
some flakes.

https://cloud.google.com/storage/docs/consistency#eventually_consistent_operations
https://cloud.google.com/storage/docs/access-control/lists#modification-rules
 (see note above)

Fixes #6579

storage/integration_test.go

@@ -4986,12 +4986,12 @@ func hasRule(acl []ACLRule, rule ACLRule) bool {
 }
 
 // retry retries a function call as well as an (optional) correctness check for up
-// to 11 seconds. Both call and check must run without error in order to succeed.
+// to 60 seconds. Both call and check must run without error in order to succeed.
 // If the timeout is hit, the most recent error from call or check will be returned.
 // This function should be used to wrap calls that might cause integration test
 // flakes due to delays in propagation (for example, metadata updates).
 func retry(ctx context.Context, call func() error, check func() error) error {
-	timeout := time.After(11 * time.Second)
+	timeout := time.After(60 * time.Second)
 	var err error
 	for {
 		select {