don't create an input connection if client is null

src/Android/Avalonia.Android/AndroidInputMethod.cs

@@ -1,7 +1,6 @@
 using System;
 using Android.Content;
 using Android.Runtime;
-using Android.Text;
 using Android.Views;
 using Android.Views.InputMethods;
 using Avalonia.Android.Platform.SkiaPlatform;
@@ -99,6 +98,9 @@ namespace Avalonia.Android
         {
             _host.InitEditorInfo((topLevel, outAttrs) =>
             {
+                if (_client == null)
+                    return null;
+
                 _inputConnection = new AvaloniaInputConnection(topLevel, this);
 
                 outAttrs.InputType = options.ContentType switch