Add GA help

lib/constants.dart

@@ -61,6 +61,8 @@ const String kGitHubDiffUrl =
 const String kGitHubLangUrl =
     'https://github.com/invoiceninja/invoiceninja/blob/master/resources/lang/en/texts.php';
 const String kStatusCheckUrl = 'https://status.invoiceninja.com';
+const String kGoogleAnalyticsUrl =
+    'https://support.google.com/analytics/answer/1037249?hl=en';
 
 enum AppEnvironment {
   hosted,

lib/ui/settings/account_management.dart

@@ -15,6 +15,7 @@ import 'package:invoiceninja_flutter/ui/app/forms/app_form.dart';
 import 'package:invoiceninja_flutter/ui/app/edit_scaffold.dart';
 import 'package:invoiceninja_flutter/ui/app/forms/bool_dropdown_button.dart';
 import 'package:invoiceninja_flutter/ui/app/forms/decorated_form_field.dart';
+import 'package:invoiceninja_flutter/ui/app/forms/learn_more.dart';
 import 'package:invoiceninja_flutter/ui/app/icon_text.dart';
 import 'package:invoiceninja_flutter/ui/app/lists/list_divider.dart';
 import 'package:invoiceninja_flutter/ui/app/scrollable_listview.dart';
@@ -207,10 +208,13 @@ class _AccountManagementState extends State<AccountManagement>
           ScrollableListView(children: [
             FormCard(
               children: [
-                DecoratedFormField(
+                LearnMoreUrl(
+                  url: kGoogleAnalyticsUrl,
+                  child: DecoratedFormField(
                     label: localization.googleAnalyticsTrackingId,
                     controller: _trackingIdController,
                   ),
+                ),
               ],
             )
           ]),