Guard bad supported features for Google

[balloob]

Breaking change

Proposed change

Google Assistant could blow up if a bad integration inserted a string value for supported features into the state machine.

Fixes #40717

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[probot-home-assistant]

Hey there @home-assistant/cloud, mind taking a look at this pull request as its been labeled with an integration (google_assistant) you are listed as a codeowner for? Thanks!
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[elupus]

Should we block this in the base platforms instead (entity, light...)?

But should really hurt to also handle it here.

[balloob]

The goal is to get it to annoy the user enough that it will report it to us :)

[elupus]

Sure. But now we only annoy google assistant users :)

[elupus]

Ps. We could annoy them much much better by making a google home announcement of the error ;)

[balloob]

@elupus #37663 😉

[pvizeli]

We should prevent to write bad states/entity to statemachine. However, a check like that is also not bad if we have this check

[balloob]

I rather not add more checks to writing states. That will be a developer feature that would introduce runtime cost for normal usage.