allow empty address forms in contact address form validation

lib/models/contact_address_entry_data.dart

@@ -33,6 +33,19 @@ class AddressEntryData extends ChangeNotifier {
     notifyListeners();
   }
 
+  bool get isEmpty {
+    if (address != null && address!.isNotEmpty) {
+      return false;
+    }
+    if (addressLabel != null && addressLabel!.isNotEmpty) {
+      return false;
+    }
+    if (coin != null) {
+      return false;
+    }
+    return true;
+  }
+
   bool get isValid {
     if (_address == null || coin == null || _addressLabel == null) {
       return false;

lib/providers/ui/address_book_providers/valid_contact_state_provider.dart

@@ -5,10 +5,19 @@ final validContactStateProvider =
     StateProvider.autoDispose.family<bool, List<int>>((ref, ids) {
   bool isValid = true;
 
+  bool hasAtLeastOneValid = false;
+
   for (int i = 0; i < ids.length; i++) {
-    isValid = isValid &&
+    final _valid = ref.watch(
-        ref.watch(
+        addressEntryDataProvider(ids[i]).select((value) => value.isValid));
-            addressEntryDataProvider(ids[i]).select((value) => value.isValid));
+
+    final _isEmpty = ref.watch(
+        addressEntryDataProvider(ids[i]).select((value) => value.isEmpty));
+
+    isValid = isValid && (_valid || _isEmpty);
+    if (_valid) {
+      hasAtLeastOneValid = true;
+    }
   }
-  return isValid;
+  return isValid && hasAtLeastOneValid;
 });