Update tests for stage without deps

tests/mock_things/mock_cancel.py

@@ -1,19 +0,0 @@
-"""Create a fake CancelHook used instead of a dependency, it cannot be used to cancel!
-
-Certain actions require a CancelHook to be supplied if called directly. The only method
-we use from the LabThings CancelHook is ``sleep()``. The CanceHook ``sleep()`` works
-exactly like ``time.sleep()`` except with raise an ``InvocationCancelledError`` if the
-server receives a cancellation request.
-
-This is just an object with a sleep method.
-"""
-
-import time
-
-
-class MockCancel:
-    """A class to use when directly calling an action with CancelHook dependency."""
-
-    def sleep(self, time_in_seconds: float) -> None:
-        """Sleep for the input number of seconds."""
-        time.sleep(time_in_seconds)