test [nfc]: Have eg.user accept dateJoined and role

Author: sm-sayedi

test/example_data.dart

@@ -80,8 +80,10 @@ User user({
   String? deliveryEmail,
   String? email,
   String? fullName,
+  String? dateJoined,
   bool? isActive,
   bool? isBot,
+  UserRole? role,
   String? avatarUrl,
   Map<int, ProfileFieldUserData>? profileData,
 }) {
@@ -92,13 +94,13 @@ User user({
     deliveryEmail: effectiveDeliveryEmail,
     email: email ?? effectiveDeliveryEmail,
     fullName: fullName ?? 'A user', // TODO generate example names
-    dateJoined: '2023-04-28',
+    dateJoined: dateJoined ?? '2023-04-28',
     isActive: isActive ?? true,
     isBillingAdmin: false,
     isBot: isBot ?? false,
     botType: null,
     botOwnerId: null,
-    role: UserRole.member,
+    role: role ?? UserRole.member,
     timezone: 'UTC',
     avatarUrl: avatarUrl,
     avatarVersion: 0,