Use 1es-windows-2019 again (#41547)

.azure/pipelines/jobs/default-build.yml

@@ -124,7 +124,7 @@ jobs:
         ${{ if eq(variables['System.TeamProject'], 'internal') }}:
           name: NetCore1ESPool-Internal
           # Visual Studio Enterprise - contains some stuff, like SQL Server and IIS Express, that we use for testing
-          demands: ImageOverride -equals Build.Server.Amd64.VS2019
+          demands: ImageOverride -equals 1es-windows-2019
     ${{ if ne(parameters.container, '') }}:
       container: ${{ parameters.container }}
     ${{ if ne(parameters.disableComponentGovernance, '') }}: