Remove error that users are running into (#1198)

### Description
Some customers have a misconfiguration (I think) that is triggering this
error. We should roll out a validation to get that fixed instead of
blocking all their queries with this error.

metricflow-semantics/metricflow_semantics/model/semantics/linkable_element.py

@@ -336,10 +336,6 @@ def __post_init__(self) -> None:  # noqa: D105
             self.derived_from_semantic_models
         ), "There must be at least one semantic model from which the metric is derived."
 
-        assert (
-            self.join_on_entity not in self.entity_links
-        ), "Entity links have been misconfigured. They should not include the join_on_entity."
-
 
 @dataclass(frozen=True)
 class SemanticModelToMetricSubqueryJoinPath: