Fix verifyformat`

Author: ankitaj224

firebase-installations/src/main/java/com/google/firebase/installations/local/IidStore.java

@@ -30,7 +30,6 @@
 import java.security.PublicKey;
 import java.security.spec.InvalidKeySpecException;
 import java.security.spec.X509EncodedKeySpec;
-import java.util.Optional;
 
 public class IidStore {
   private static final String IID_SHARED_PREFS_NAME = "com.google.android.gms.appid";