fix(minimal): ensure global usings contains using for ApiGroupNames for handlers to be able to build

Author: Per Kops

src/Atc.Rest.ApiGenerator.Framework.Minimal/ProjectGenerator/ServerDomainGenerator.cs

@@ -261,6 +261,7 @@ public void MaintainGlobalUsings(
         var apiGroupNames = openApiDocument.GetApiGroupNames();
 
         requiredUsings.AddRange(apiGroupNames.Select(x => NamespaceFactory.Create(apiProjectName, NamespaceFactory.CreateWithApiGroupName(x, settings.ContractsNamespace))));
+        requiredUsings.AddRange(apiGroupNames.Select(x => NamespaceFactory.Create(settings.ProjectName, NamespaceFactory.CreateWithApiGroupName(x, settings.HandlersNamespace))));
 
         GlobalUsingsHelper.CreateOrUpdate(
             logger,