Fix the server exception when validating an invalid local reference

'fetcher == null' is ok for a local reference.

Unfortunately, there are now two messages with the same meaning:
- one from the ProfileValidation
- one from the code in this location

hapi-fhir-validation/src/main/java/org/hl7/fhir/r4/validation/InstanceValidator.java

@@ -1563,10 +1563,13 @@ public class InstanceValidator extends BaseValidator implements IResourceValidat
 
     if (pol.checkExists()) {
       if (we == null) {
-        if (fetcher == null)
+        if (fetcher == null) {
+          if (!refType.equals("contained"))
             throw new FHIRException("Resource resolution services not provided");
+        } else {
           we = fetcher.fetch(hostContext.appContext, ref);
         }
+      }
       rule(errors, IssueType.STRUCTURE, element.line(), element.col(), path, we != null, "Unable to resolve resource '"+ref+"'");
     }