Make all_parents_must_converge settable when creating node

When targeting, ../workflow_job_templates/id#/workflow_nodes/ endpoint,
user could not set all_parents_must_converge to true.

awx issue ansible#7063

awx/api/serializers.py

@@ -3600,7 +3600,7 @@ def validate(self, attrs):
             ujt = self.instance.unified_job_template
         if ujt is None:
             ret = {}
-            for fd in ('workflow_job_template', 'identifier'):
+            for fd in ('workflow_job_template', 'identifier', 'all_parents_must_converge'):
                 if fd in attrs:
                     ret[fd] = attrs[fd]
             return ret

awx/main/tests/functional/api/test_workflow_node.py

@@ -71,6 +71,18 @@ def test_node_accepts_prompted_fields(inventory, project, workflow_job_template,
          user=admin_user, expect=201)
 
 
+@pytest.mark.django_db
+@pytest.mark.parametrize("field_name, field_value", [
+    ('all_parents_must_converge', True),
+    ('all_parents_must_converge', False),
+])
+def test_create_node_with_field(field_name, field_value, workflow_job_template, post, admin_user):
+    url = reverse('api:workflow_job_template_workflow_nodes_list',
+                  kwargs={'pk': workflow_job_template.pk})
+    res = post(url, {field_name: field_value}, user=admin_user)
+    assert res.data[field_name] == field_value
+
+
 @pytest.mark.django_db
 class TestApprovalNodes():
     def test_approval_node_creation(self, post, approval_node, admin_user):