Remove LangVersion from server-side Blazor project template (#13094)

Fixes #9168

Author: pranavkm

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

@@ -2,7 +2,6 @@
 
   <PropertyGroup>
     <TargetFramework>netcoreapp3.0</TargetFramework>
-    <LangVersion>7.3</LangVersion>
     <UserSecretsId Condition="'$(IndividualAuth)' == 'True' OR '$(OrganizationalAuth)' == 'True'">aspnet-BlazorServerWeb_CSharp-53bc9b9d-9d6a-45d4-8429-2a2761773502</UserSecretsId>
     <WebProject_DirectoryAccessLevelKey Condition="'$(OrganizationalAuth)' == 'True' AND '$(OrgReadAccess)' != 'True'">0</WebProject_DirectoryAccessLevelKey>
     <WebProject_DirectoryAccessLevelKey Condition="'$(OrganizationalAuth)' == 'True' AND '$(OrgReadAccess)' == 'True'">1</WebProject_DirectoryAccessLevelKey>