Don't turn off BTRV after the lowest setpoint temperatur is reached (ex. window was opened)

[TBSniller]

Motivation:

After an open window was closed, the BTRVs HVACMode often changes to the OFF state, which lead to cold rooms

Changes:

• Removed the lines which are responsible for switching BTRV to HEAT or OFF, if the new _new_heating_setpoint is the real TRVs lowest temperature:
  

  better_thermostat/custom_components/better_thermostat/events/trv.py

  Lines 204 to 209 in 6a349d9

  	if self.real_trvs[entity_id]["advanced"].get("no_off_system_mode", False):
  	if _new_heating_setpoint == self.real_trvs[entity_id]["min_temp"]:
  	self.bt_hvac_mode = HVACMode.OFF
  	else:
  	self.bt_hvac_mode = HVACMode.HEAT
  	_main_change = True

I'm not sure for what these lines are for. When the window is opened, the real TRV is automatically set to the lowest temp. Then, through these lines, the BTRV is turned off.
Don't know why the BTRV is controlled here? Maybe to reflect such changes to the UI, or is there a specific reason?

If it was for the UI feedback, then these lines make a bit sense, as the BTRV would be set back to HEAT, if _new_heating_setpoint goes back to a higher temperature. But then the issue here is, that this statement is never reached again, as its blocked by this if statement

better_thermostat/custom_components/better_thermostat/events/trv.py

Line 160 in 6a349d9

and self.bt_hvac_mode is not HVACMode.OFF

So if there wasn't a real need for this kind of behavior, my changes should be enough.
Otherwise I think the logic must be fixed, so statement is reached again that turnes the BTRVs HVACMode back to HEAT. But in my opinion, it could still lead to more problems, if BTRV controls it's own HVACMode.

Related issue (check one):

• fixes Open and close a window most of the time doesn't reset heating mode correctly #1234 and properly BT turns HVAC mode to off when window is opened #1270
• there is no related issue ticket

Checklist (check one):

• I did not change any code (e.g. documentation changes)
• The code change is tested and works locally.

Test-Hardware list (for code changes)

Debian 11 VM 4GB and devcontainers according to CONTRIBUTION.md

HA Version: 2024.9.1
Zigbee2MQTT Version: 1.40.1-1
TRV Hardware: TS0601 (BRT-100-TRV)

New device mappings

• I avoided any changes to other device mappings
• There are no changes in climate.py