Migrate powerwall unique ids to use the gateway din

[bdraco]

Note this PR cannot be back-ported because its relies on previous PRs in dev only. Please do not tag for a patch release.

Proposed change

We used the powerwall serial numbers before the api had the gateway din. Now that older firmware that doesn't expose the din isn't supported by library, and users have multiple gateways this is no longer unique enough.

fixes #100065

Type of change

• Dependency upgrade
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• This PR fixes or closes issue: fixes #
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[home-assistant]

Hey there @jrester, @daniel-simpson, mind taking a look at this pull request as it has been labeled with an integration (powerwall) you are listed as a code owner for? Thanks!

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[bdraco]

Works great but needs at least a test to make sure the device and one entity is migrated correctly

[bdraco]

cd /config
curl -o- -sSL https://gist.githubusercontent.com/bdraco/43f8043cb04b9838383fd71353e99b18/raw/core_integration_pr | bash /dev/stdin -d powerwall -p 107509

[bdraco]

thanks