CompileAvaloniaXamlTask - handle no-pdb compilations

[ltetak]

What does the pull request do?

Fix build of C# projects with no PDB.

What is the current behavior?

Error is thrown by msbuild

***\.nuget\packages\avalonia\11.1.0-beta2\buildTransitive\AvaloniaBuildTasks.targets(138,5): error MSB
4018: The "CompileAvaloniaXamlTask" task failed unexpectedly. [***]
***\.nuget\packages\avalonia\11.1.0-beta2\buildTransitive\AvaloniaBuildTasks.targets(138,5): error MSB
4018: System.IO.FileNotFoundException: Could not find file '***/net7.0-windows\win-x64\Application.pdb'. 

This was caused by this optimization 223cfab
The original code checked for the existence of the PDB file but the new code does not.

To test this add this to any csproj file in the project with XAML files.

<PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
   <DebugType>none</DebugType>
 </PropertyGroup>

What is the updated/expected behavior with this PR?

If there is no PDB then there is nothing to copy. Just ignore it.

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0047731-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[jmacato]

@cla-avalonia recheck

[cla-avalonia]

• All contributors have signed the CLA.

[ltetak]

@cla-avalonia agree

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0047966-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]