Remove unnecessary generic type arguments

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=175155365

java/google/registry/request/auth/AuthModule.java

@@ -30,7 +30,7 @@ public class AuthModule {
   @Provides
   ImmutableList<AuthenticationMechanism> provideApiAuthenticationMechanisms(
       OAuthAuthenticationMechanism oauthAuthenticationMechanism) {
-    return ImmutableList.<AuthenticationMechanism>of(
+    return ImmutableList.of(
         oauthAuthenticationMechanism);
   }
 

java/google/registry/request/auth/AuthResult.java

@@ -37,7 +37,7 @@ public abstract class AuthResult {
   }
 
   public static AuthResult create(AuthLevel authLevel) {
-    return new AutoValue_AuthResult(authLevel, Optional.<UserAuthInfo>empty());
+    return new AutoValue_AuthResult(authLevel, Optional.empty());
   }
 
   public static AuthResult create(AuthLevel authLevel, @Nullable UserAuthInfo userAuthInfo) {

java/google/registry/request/auth/UserAuthInfo.java

@@ -39,7 +39,7 @@ public abstract class UserAuthInfo {
 
   public static UserAuthInfo create(
       User user, boolean isUserAdmin) {
-    return new AutoValue_UserAuthInfo(user, isUserAdmin, Optional.<OAuthTokenInfo>empty());
+    return new AutoValue_UserAuthInfo(user, isUserAdmin, Optional.empty());
   }
 
   public static UserAuthInfo create(