[python] Fixes endpoint overload type hint + required property not in properties (#13790)

* Adds endpoint overload type hint fix to template

* Samples regenerated

* Adds fix for required property not in properties

* Regenerates samples

samples/openapi3/client/petstore/python/test/test_models/test_object_with_all_of_with_req_test_prop_from_unset_add_prop.py

@@ -0,0 +1,25 @@
+# coding: utf-8
+
+"""
+    OpenAPI Petstore
+
+    This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\  # noqa: E501
+
+    The version of the OpenAPI document: 1.0.0
+    Generated by: https://openapi-generator.tech
+"""
+
+import unittest
+
+import petstore_api
+from petstore_api.model.object_with_all_of_with_req_test_prop_from_unset_add_prop import ObjectWithAllOfWithReqTestPropFromUnsetAddProp
+from petstore_api import configuration
+
+
+class TestObjectWithAllOfWithReqTestPropFromUnsetAddProp(unittest.TestCase):
+    """ObjectWithAllOfWithReqTestPropFromUnsetAddProp unit test stubs"""
+    _configuration = configuration.Configuration()
+
+
+if __name__ == '__main__':
+    unittest.main()

samples/openapi3/client/petstore/python/test/test_models/test_object_with_optional_test_prop.py

@@ -0,0 +1,25 @@
+# coding: utf-8
+
+"""
+    OpenAPI Petstore
+
+    This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\  # noqa: E501
+
+    The version of the OpenAPI document: 1.0.0
+    Generated by: https://openapi-generator.tech
+"""
+
+import unittest
+
+import petstore_api
+from petstore_api.model.object_with_optional_test_prop import ObjectWithOptionalTestProp
+from petstore_api import configuration
+
+
+class TestObjectWithOptionalTestProp(unittest.TestCase):
+    """ObjectWithOptionalTestProp unit test stubs"""
+    _configuration = configuration.Configuration()
+
+
+if __name__ == '__main__':
+    unittest.main()