[Build Fix] set AndroidClassParser build property to class-parse

Build reported these warnings:

warning XA4231: The Android class parser value 'jar2xml' is deprecated and will be removed in a future version of Xamarin.Android. Update the project properties to use 'class-parse'

In the code <AndroidClassParser> is not specified, so by default it uses
'jar2xml'. So set its value to 'class-parse'.

See:
https://github.com/xamarin/xamarin-android/blob/main/Documentation/guides/messages/xa4231.md
https://github.com/xamarin/xamarin-android/issues/1319

Moving to class-parse instead of jar2xml also fixes issues when building with Java 11 & Xamarin < 12.2
Because of:
- 94e21c7aaa
If the change wasn't done, we would have to stick with JDK-8

src/Kp2aKeyboardBinding/Kp2aKeyboardBinding.csproj

@@ -13,6 +13,7 @@
     <AndroidUseLatestPlatformSdk>false</AndroidUseLatestPlatformSdk>
     <TargetFrameworkVersion>v10.0</TargetFrameworkVersion>
     <AndroidCodegenTarget>XAJavaInterop1</AndroidCodegenTarget>
+    <AndroidClassParser>class-parse</AndroidClassParser>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>True</DebugSymbols>
@@ -68,4 +69,4 @@
   <ItemGroup>
     <Folder Include="libs\" />
   </ItemGroup>
-</Project>
+</Project>