tests: remove stdlib detail from unit test

This message is a detail of the stdlib and could change and it doesn't
matter to us. The important thing that this test is testing is that
base.UAEntitlement cannot be instantiated itself and will raise a
TypeError.

uaclient/entitlements/tests/test_base.py

@@ -154,14 +154,8 @@ def factory(
 class TestUaEntitlement:
     def test_entitlement_abstract_class(self):
         """UAEntitlement is abstract requiring concrete methods."""
-        with pytest.raises(TypeError) as excinfo:
+        with pytest.raises(TypeError):
             base.UAEntitlement()
-        expected_msg = (
-            "Can't instantiate abstract class UAEntitlement with abstract"
-            " methods _perform_disable, _perform_enable, application_status,"
-            " description, name, title"
-        )
-        assert expected_msg == str(excinfo.value)
 
     def test_init_default_sets_up_uaconfig(self):
         """UAEntitlement sets up a uaconfig instance upon init."""