Allow is_state to accept a list of values

[mdegat01]

Proposed change

If is_state is passed a list of values it returns true if the state of the entity is in the list. Essentially this:

{{ states('binary_sensor.test') is in ['on', 'off'] }}

would become this after this PR:

{{ is_state('binary_sensor.test', ['on', 'off']) }}

Also this really helps with expand use cases as this:

{{ expand(my_list_of_entities) | selectattr('state', 'in', ['on', 'off'])
    | map(attribute='entity_id') | list }}

becomes this:

{{ my_list_of_entities | select('is_state', ['on', 'off']) | list }}

This is not a breaking change because a state cannot be a list. That's also why is_state_attr is not modified in the same way because an attribute can be a list.

Came up because I was auditing my templates after #79473 and realized now expand is really only needed in two cases:

1. When using last_updated, last_changed or context
2. When you want to select or reject based on the state or an attribute and the comparator is not equals (in, gt, lt, etc.)

This small change further whittled down the need for complex templates with expand as it means in comparisons based on state can be done without it.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request: Allow is_state to accept a list of values home-assistant.io#25031

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

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

• Documentation added/updated for www.home-assistant.io

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• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• For the updated dependencies - a link to the changelog, or at minimum a diff between library versions is added to the PR description.
• Untested files have been added to .coveragerc.

To help with the load of incoming pull requests:

• I have reviewed two other open pull requests in this repository.

[frenck]

Since @mdegat01 is not available soon, I've taken the freedom to add a small change. Could use a second pair of eyes on it now (as I've changed it).

Also, opened up a documentation PR: home-assistant/home-assistant.io#25031