skip invalid field check for suburls

Author: tschaume

mp_api/client/core/client.py

@@ -458,13 +458,14 @@ def _query_resource(
             if isinstance(fields, str):
                 fields = [fields]
 
-            invalid_fields = [
-                f for f in fields if f.split(".", 1)[0] not in self.available_fields
-            ]
-            if invalid_fields:
-                raise MPRestError(
-                    f"invalid fields requested: {invalid_fields}. Available fields: {self.available_fields}"
-                )
+            if not suburl:
+                invalid_fields = [
+                    f for f in fields if f.split(".", 1)[0] not in self.available_fields
+                ]
+                if invalid_fields:
+                    raise MPRestError(
+                        f"invalid fields requested: {invalid_fields}. Available fields: {self.available_fields}"
+                    )
 
             criteria["_fields"] = ",".join(fields)