ifcopenshell.validate to catch invalid entities used in entities attributes #6409

Example

```
For instance:
    # 1 =IFCCARTESIANPOINT((5.,5.,nan.));
Entity with name 'nan.' not found in schema 'IFC4'
```

src/ifcopenshell-python/test/fixtures/validate/fail-invalid-entity-in-attribute.ifc

@@ -0,0 +1,10 @@
+ISO-10303-21;
+HEADER;
+FILE_DESCRIPTION(('ViewDefinition [CoordinationView]'),'2;1');
+FILE_NAME('','2022-10-01T16:31:47',(''),(''),'IfcOpenShell 0.7.0','IfcOpenShell 0.7.0','');
+FILE_SCHEMA(('IFC4'));
+ENDSEC;
+DATA;
+#1=IFCCARTESIANPOINT((5.,5.,nan.));
+ENDSEC;
+END-ISO-10303-21;

src/ifcparse/IfcParse.cpp

@@ -726,7 +726,7 @@ void IfcParse::IfcFile::load(unsigned entity_instance_name, const IfcParse::enti
                     context.push(simple_type_instance);
                     simple_type_instance->file_ = this;
                 } catch (IfcException& e) {
-                    Logger::Message(Logger::LOG_ERROR, e.what());
+                    Logger::Message(Logger::LOG_ERROR, std::string(e.what()) + " at offset " + std::to_string(next.startPos));
                     // #4070 We didn't actually capture an aggregate entry, undo length increment.
                     return_value--;
                 }