Fix AutomationProperties.HelpText on macos (#17046)

* fix Automation.HelpText on windows

* fix AutomationProperties.HelpText on macos

* change breaking abstract to virtual

* only fall back to tooltip if string

* remove duplicate override

* fix AutomationProperties.HelpText on macos

native/Avalonia.Native/src/OSX/automation.mm

@@ -149,6 +149,11 @@
     return [super accessibilityTitle];
 }
 
+- (NSString *)accessibilityHelp
+{
+    return GetNSStringAndRelease(_peer->GetHelpText()); 
+}
+
 - (id)accessibilityValue
 {
     if (_peer->IsRangeValueProvider())

src/Avalonia.Native/AvnAutomationPeer.cs

@@ -39,6 +39,7 @@ namespace Avalonia.Native
         public IAvnString ClassName => _inner.GetClassName().ToAvnString();
         public IAvnAutomationPeer? LabeledBy => Wrap(_inner.GetLabeledBy());
         public IAvnString Name => _inner.GetName().ToAvnString();
+        public IAvnString HelpText => _inner.GetHelpText().ToAvnString();
         public IAvnAutomationPeer? Parent => Wrap(_inner.GetParent());
         public IAvnAutomationPeer? VisualRoot => Wrap(_inner.GetVisualRoot());
 

src/Avalonia.Native/avn.idl

@@ -1219,6 +1219,8 @@ interface IAvnAutomationPeer : IUnknown
      bool IsValueProvider();
      IAvnString* ValueProvider_GetValue();
      void ValueProvider_SetValue(char* value);
+
+     IAvnString* GetHelpText();
 }
 
 [uuid(b00af5da-78af-4b33-bfff-4ce13a6239a9)]