Restoring most resolvers in Compat7

src/Umbraco.Web/HealthCheck/HeathCheckCollectionBuilder.cs

@@ -11,6 +11,8 @@ namespace Umbraco.Web.HealthCheck
 
         protected override HealthCheckCollectionBuilder This => this;
 
+        // note: in v7 they were per-request, not sure why?
+        // the collection is injected into the controller & there's only 1 controller per request anyways
         protected override ILifetime CollectionLifetime => null; // transient!
     }
 }