Add import to use GIDAccountDetailTypeAgeOver18.

GoogleSignIn/Sources/GIDVerifyAccountDetail/Implementations/GIDVerifyAccountDetail.m

@@ -74,6 +74,8 @@
   [self verifyAccountDetailsInteractivelyWithOptions:options];
 }
 
+#pragma mark - Authentication flow
+
 - (void)verifyAccountDetailsInteractivelyWithOptions:(GIDSignInInternalOptions *)options {
   if (!options.interactive) {
     return;

GoogleSignIn/Tests/Unit/GIDVerifyAccountDetailTest.m

@@ -16,6 +16,7 @@
 
 #if TARGET_OS_IOS
 #import "GoogleSignIn/Sources/Public/GoogleSignIn/GIDVerifyAccountDetail.h"
+#import "GoogleSignIn/Sources/Public/GoogleSignIn/GIDVerifiableAccountDetail.h"
 
 #import "GoogleSignIn/Tests/Unit/GIDFakeMainBundle.h"