Incomplete fixes for #34 and #35

[MrXANA91]

PR #37 and #38 don't seem to have solved the issues #34 and #35

• TEMP_CELSIUS const is probably still in use somewhere else in the integration
• Simply adding ClimateEntityFeature.TURN_OFF and ClimateEntityFeature.TURN_ON is not enough to clear the deprecation warning

---

Yeah sorry I messed up.
I will look into it later today to check what I've missed and make sure the changes I'll implement really solve the issues this time.

[MrXANA91]

• TEMP_CELSIUS const :
  • replace references found in water_heater.py
• ClimateEntityFeature : according to https://developers.home-assistant.io/blog/2024/01/24/climate-climateentityfeatures-expanded/
  • explicitly implement the turn_off method
  • set a _enable_turn_on_off_backwards_compatibility variable to false

[MrXANA91]

From #40 (comment)

This has been tested on my HA instance :

• effectively removes the warnings
• no issues using the Climate's turn_off and turn_on services