improve error messages for additional accounts

lib/src/localization/generated/app_localizations.dart

@@ -2887,8 +2887,14 @@ abstract class AppLocalizations {
   /// No description provided for @additionalUserAddError.
   ///
   /// In en, this message translates to:
-  /// **'Could not add additional user. Try again later.'**
+  /// **'{username} could not be added, please try again later.'**
-  String get additionalUserAddError;
+  String additionalUserAddError(Object username);
+
+  /// No description provided for @additionalUserAddErrorNotInFreePlan.
+  ///
+  /// In en, this message translates to:
+  /// **'{username} is already on a paid plan and therefore could not be added.'**
+  String additionalUserAddErrorNotInFreePlan(Object username);
 
   /// No description provided for @additionalUserAddButton.
   ///

lib/src/localization/generated/app_localizations_de.dart

@@ -1601,8 +1601,14 @@ class AppLocalizationsDe extends AppLocalizations {
   String get privacyPolicy => 'Datenschutzerklärung';
 
   @override
-  String get additionalUserAddError =>
+  String additionalUserAddError(Object username) {
-      'Es konnte kein zusätzlicher Nutzer hinzugefügt werden. Versuche es später noch einmal.';
+    return '$username konnte nicht hinzugefügt werden, bitte versuche es später noch einmal.';
+  }
+
+  @override
+  String additionalUserAddErrorNotInFreePlan(Object username) {
+    return '$username hat bereits einen bezahlten Tarif und konnte daher nicht hinzugefügt werden.';
+  }
 
   @override
   String additionalUserAddButton(Object limit, Object used) {

lib/src/localization/generated/app_localizations_en.dart

@@ -1590,8 +1590,14 @@ class AppLocalizationsEn extends AppLocalizations {
   String get privacyPolicy => 'Privacy policy';
 
   @override
-  String get additionalUserAddError =>
+  String additionalUserAddError(Object username) {
-      'Could not add additional user. Try again later.';
+    return '$username could not be added, please try again later.';
+  }
+
+  @override
+  String additionalUserAddErrorNotInFreePlan(Object username) {
+    return '$username is already on a paid plan and therefore could not be added.';
+  }
 
   @override
   String additionalUserAddButton(Object limit, Object used) {

lib/src/localization/generated/app_localizations_sv.dart

@@ -1590,8 +1590,14 @@ class AppLocalizationsSv extends AppLocalizations {
   String get privacyPolicy => 'Privacy policy';
 
   @override
-  String get additionalUserAddError =>
+  String additionalUserAddError(Object username) {
-      'Could not add additional user. Try again later.';
+    return '$username could not be added, please try again later.';
+  }
+
+  @override
+  String additionalUserAddErrorNotInFreePlan(Object username) {
+    return '$username is already on a paid plan and therefore could not be added.';
+  }
 
   @override
   String additionalUserAddButton(Object limit, Object used) {

lib/src/localization/translations

@@ -1 +1 @@
-Subproject commit 471fed328ff1bf9316e9b86456ecdd68f4cfabca
+Subproject commit c1dc14a53ff2854389a50f4aaeb26946ff925367

lib/src/views/settings/subscription/additional_users.view.dart

@@ -72,9 +72,30 @@ class _AdditionalUsersViewState extends State<AdditionalUsersView> {
     for (final selectedUserId in selectedUserIds) {
       final res = await apiService.addAdditionalUser(Int64(selectedUserId));
       if (res.isError && mounted) {
+        final contact =
+            await twonlyDB.contactsDao.getContactById(selectedUserId);
+        if (contact != null && mounted) {
+          if (res.error == ErrorCode.UserIsNotInFreePlan) {
             ScaffoldMessenger.of(context).showSnackBar(
-          SnackBar(content: Text(context.lang.additionalUserAddError)),
+              SnackBar(
+                content: Text(
+                  context.lang.additionalUserAddErrorNotInFreePlan(
+                    getContactDisplayName(contact),
+                  ),
+                ),
+              ),
             );
+          } else {
+            ScaffoldMessenger.of(context).showSnackBar(
+              SnackBar(
+                content: Text(
+                  context.lang
+                      .additionalUserAddError(getContactDisplayName(contact)),
+                ),
+              ),
+            );
+          }
+        }
       }
     }
     await initAsync(force: true);