Update service domain for mill from 'climate' to 'mill'

[raman325]

Breaking Change:

This change breaks existing service call references to the climate.mill_set_room_temperature services by changing the service calls to be mill.set_room_temperature. My understanding is that because this is not a service provided by the base climate component, it should live in the domain of the mill component instead. If that's the case, then it also makes sense to update the service name.

Description:

Update the domain and service name for mill.set_room_temperature. See this comment for context: #28890 (comment)

Related issue (if applicable): Related to #27289

Pull request with documentation for home-assistant.io (if applicable): home-assistant/home-assistant.io#11307

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly. Update and include derived files by running python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt by running python3 -m script.gen_requirements_all.
• Untested files have been added to .coveragerc.

[probot-home-assistant]

Hey there @Danielhiversen, mind taking a look at this pull request as its been labeled with a integration (mill) you are listed as a codeowner for? Thanks!

[frenck]

Thanks, @raman325! 👍