Fix DynaCool driver init and temperature_setpoint cache update

docs/changes/newsfragments/+dynacool-fixes.improved_driver

@@ -0,0 +1,14 @@
+Fixed three bugs in :class:`qcodes.instrument_drivers.QuantumDesign.DynaCoolPPMS.DynaCool.DynaCool`
+that prevented the driver from instantiating and from updating the
+``temperature_setpoint`` cache:
+
+- ``block_while_ramping_temperature`` is now created with ``set_cmd=None`` /
+  ``get_cmd=None`` so it behaves as a settable cache-only parameter, instead of
+  ``set_cmd=False`` / ``get_cmd=False`` which made it read-only and rejected
+  the supplied ``initial_value``.
+- Removed the duplicate ``instrument=self`` argument from the
+  ``blocking_t_state_check_interval`` parameter creation, which is supplied
+  automatically by ``add_parameter`` and was raising on construction.
+- Fixed an ``AttributeError`` when setting the temperature: the cache update
+  in ``_set_temperature_and_state`` now correctly references
+  ``self.temperature_setpoint`` rather than the non-existent ``self.setpoint``.

src/qcodes/instrument_drivers/QuantumDesign/DynaCoolPPMS/DynaCool.py

@@ -84,15 +84,14 @@ def __init__(
             label="Block instrument while ramping temperature",
             initial_value=False,
             vals=vals.Bool(),
-            get_cmd=False,
-            set_cmd=False,
+            get_cmd=None,
+            set_cmd=None,
         )
         """Parameter block_while_ramping_temperature, when set to True,
         will block further interaction while temperature is ramping to setpoint."""
 
         self.blocking_t_state_check_interval: Parameter = self.add_parameter(
             name="blocking_t_state_check_interval",
-            instrument=self,
             initial_value=0.5,
             unit="s",
             vals=vals.Numbers(0, 60),
@@ -434,7 +433,7 @@ def _temp_setter(
             while self.temperature_state() != "stable":
                 sleep(self.blocking_t_state_check_interval())
 
-        self.setpoint.cache._set_from_raw_value(values[0])
+        self.temperature_setpoint.cache._set_from_raw_value(values[0])
 
     def write(self, cmd: str) -> None:
         """