Fix Tuya Saswell TRVs causing ZHA to generate new climate entity

[TheJulianJES]

Proposed change

This works around an issue in ZHA where the updated v2 quirk for the Tuya Saswell TRV caused ZHA to generate a new climate entity.

Cause

The v2 quirk replaced an old v1 quirk in #3772. The v1 quirk changed the DEVICE_TYPE for endpoint 1 from the Tuya-reported SMART_PLUG to THERMOSTAT. As this DEVICE_TYPE is generally not used anymore, we do not change them in v2 quirks.
However, there's some old legacy code in ZHA that changes unique IDs depending on if ZHA and HA platform match. This is rarely the case (the code is somewhat bad), but for thermostats, it unfortunately applied before: https://github.com/zigpy/zha/blob/d6bb4a89ff857137e96b2932f711f1bdb2fbe80b/zha/application/discovery.py#L564-L573

So, we need to change back the profile type to THERMOSTAT for Tuya Saswell TRVs again, like the v1 quirk did.
In the future, we should really remove that code in ZHA and migrate existing UIDs to new ones.

Other v2 TRV quirks

Some other v2 TRV quirks were added in 0.0.131 too, but I think this was the only TRV quirk that replaced an existing v1 quirk. If we were to change this for all v2 quirks, we'd break the entity used by everyone in 2025.2.0 and 2025.1.

But if they were using custom quirks before, they would have already changed the DEVICE_TYPE to THERMOSTAT. E.g. this one: https://github.com/jacekk015/zha_quirks/blob/dcfc3beb98008bbb40780dbcf4f38af82c117e5d/ts0601_trv_me167.py#L466-L493
So, for those people, it already broke in 2025.2.x and adding this to all v2 TRV quirks would restore functionality.

Now, we don't support custom quirks, of course. But it's an unfortunate reality that they're used a lot in production instances, without being contributed upstream. Maybe we do want to add this to all Tuya v2 TRV (+ thermostat?) quirks for now, so they cause ZHA to use the same unique ID?

(cc @prairiesnpr for thoughts on this when you're back 😄)

Additional information

• Cause related to: Remove single entity limit in some circumstances zha#158
• Noticed in: Update to Core 2025.2.X mixing up my Thermostat Entitys home-assistant/core#138058
• There are still other issues with the v2 quirk for some Tuya TRVs, not fixed by this, see this thread:
  [BUG] Tuya TS0601 TRV temperature offset not exposed after 2025.2.0 #3837

Checklist

• The changes are tested and work correctly
• pre-commit checks pass / the code has been formatted using Black
• Tests have been added to verify that the new code works

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.93%. Comparing base (8b92f69) to head (f2e5e24).

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #3846   +/-   ##
=======================================
  Coverage   90.93%   90.93%           
=======================================
  Files         326      326           
  Lines       10591    10592    +1     
=======================================
+ Hits         9631     9632    +1     
  Misses        960      960           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.