Update JS SDK version and refactor Sdk element usage

- The SDK version depends on the VS installation and version 1.0.3864779 is not available on a machine with VS 2026.
- Updated JavaScript SDK version from 1.0.3864779 to 1.0.5581896 in the project file to support VS 2026.
- Moved the Sdk attribute from the <Project> tag to a dedicated <Sdk> element to keep previous versions as references.

Author: rvuistin

src/ElectronNET.Host/ElectronNET.Host.esproj

@@ -1,4 +1,6 @@
-<Project Sdk="Microsoft.VisualStudio.JavaScript.Sdk/1.0.3864779">
+<Project>
+  <!--<Sdk Name="Microsoft.VisualStudio.JavaScript.SDK" Version="1.0.3864779" />-->
+  <Sdk Name="Microsoft.VisualStudio.JavaScript.SDK" Version="1.0.5581896" />
   <ItemGroup>
     <None Include=".vscode\tasks.json" />
   </ItemGroup>