Remove custom Bosch pi_heating_demand attr for RBSH-RTH0-ZB-EU (#4329)

Remove custom Bosch pi_heating_demand attribute for RBSH-RTH0-ZB-EU due to conflicting with thermostat cooling mode.
This thermostat reports correct status through system_mode and running_mode attributes.

See home-assistant/core#151763

Author: mrrstux

zhaquirks/bosch/rbsh_rth0_zb_eu.py

@@ -16,9 +16,6 @@
 # Mode of operation with values BoschOperatingMode.
 OPERATING_MODE_ATTR_ID = 0x4007
 
-# Valve position: 0% - 100%
-VALVE_POSITION_ATTR_ID = 0x4020
-
 # Window open switch (changes to a lower target temperature when on).
 WINDOW_OPEN_ATTR_ID = 0x4042
 
@@ -71,13 +68,6 @@ class AttributeDefs(Thermostat.AttributeDefs):
             is_manufacturer_specific=True,
         )
 
-        pi_heating_demand = ZCLAttributeDef(
-            id=VALVE_POSITION_ATTR_ID,
-            # Values range from 0-100
-            type=t.uint8_t,
-            is_manufacturer_specific=True,
-        )
-
         window_open = ZCLAttributeDef(
             id=WINDOW_OPEN_ATTR_ID,
             type=State,