connector_importer: take full control of what are the required_keys

Not forcing required default value if required_keys is defined in options.mapper

connector_importer/components/mapper.py

@@ -53,8 +53,8 @@ def required_keys(self, create=False):
         The recordset will use this to show required fields to users.
         """
         req = dict(self.required)
-        req.update(self.work.options.mapper.get("required_keys", {}))
-        return req
+
+        return self.work.options.mapper.get("required_keys", {}) or req
 
     translatable = []