Remove unnecessary newline at the end of csproj (#61302)

This brings the template in line with the `dotnet new webapi` one, where there is no lingering newline at the end of the csproj.

Author: sander1095

src/ProjectTemplates/Web.ProjectTemplates/WebApiAot-CSharp.csproj.in

@@ -14,6 +14,6 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="${MicrosoftAspNetCoreOpenApiVersion}" Condition="'$(EnableOpenAPI)' == 'True'" />
   </ItemGroup>
+  
   <!--#endif -->
-
 </Project>