Generic Unhandled Exceptions handler

Starting Uno Platform 5.4, we are generating a generic handler for Application.UnhandledException, in line with WinUI approach. When debugger is attached, unhandled framework exceptions will be logged in the debugger output by default. If you also want the debugger to break on unhandled exceptions, set the BreakOnUnhandledExceptions property to true in the .csproj:

<PropertyGroup>
  <BreakOnUnhandledExceptions>true</BreakOnUnhandledExceptions>
</PropertyGroup>

If you want to disable the generated Application.UnhandledException handler altogether, define the DISABLE_GENERATED_UNHANDLED_EXCEPTION_HANDLER constant in .csproj instead:

<PropertyGroup>
  <DefineConstants>$(DefineConstants);DISABLE_GENERATED_UNHANDLED_EXCEPTION_HANDLER</DefineConstants>
</PropertyGroup>