Fix auto upstream dep when expanding non-templated field (#23771)

If you tried to expand via xcom into a non-templated field without
explicitly setting the upstream task dependency, the scheduler would
crash because the upstream task dependency wasn't being set
automatically. It was being set only for templated fields, but now we do
it for both.

airflow/models/mappedoperator.py

@@ -300,8 +300,7 @@ def __attrs_post_init__(self):
         if self.dag:
             self.dag.add_task(self)
         for k, v in self.mapped_kwargs.items():
-            if k in self.template_fields:
-                XComArg.apply_upstream_relationship(self, v)
+            XComArg.apply_upstream_relationship(self, v)
         for k, v in self.partial_kwargs.items():
             if k in self.template_fields:
                 XComArg.apply_upstream_relationship(self, v)

tests/models/test_taskinstance.py

@@ -2835,3 +2835,23 @@ def add_one(x):
         ti.refresh_from_task(dag.get_task("add_one"))
         with pytest.raises(XComForMappingNotPushed):
             ti.run()
+
+
+def test_expand_non_templated_field(dag_maker, session):
+    """Test expand on non-templated fields sets upstream deps properly."""
+
+    class SimpleBashOperator(BashOperator):
+        template_fields = ()
+
+    with dag_maker(dag_id="product_same_types", session=session) as dag:
+
+        @dag.task
+        def get_extra_env():
+            return [{"foo": "bar"}, {"foo": "biz"}]
+
+        SimpleBashOperator.partial(task_id="echo", bash_command="echo $FOO").expand(env=get_extra_env())
+
+    dag_maker.create_dagrun()
+
+    echo_task = dag.get_task("echo")
+    assert "get_extra_env" in echo_task.upstream_task_ids