Use boolean for mqtt fan state

[emontnemery]

Proposed change

Revert parts of #39096 as requested by @MartinHjelmare

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
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• Breaking change (fix/feature causing existing functionality to break)
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[probot-home-assistant]

Hey there @home-assistant/core, mind taking a look at this pull request as its been labeled with an integration (mqtt) you are listed as a codeowner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[MartinHjelmare]

Thanks!