Graphite dependency no longer hosted by kiwigrid

[matthewelwell]

As seen here (full traceback also pasted below), kiwigrid have archived their helm charts repo here. This means that kiwigrid.github.io is no longer available, and hence our CI is failing.

Linting charts...

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 Charts to be processed:
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 flagsmith => (version: "0.77.3", path: "charts/flagsmith")
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"stable" has been added to your repositories
"bitnami" has been added to your repositories
"influxdata" has been added to your repositories
Error: failed linting charts: failed adding repo: kiwigrid=[https://kiwigrid.github.io:](https://kiwigrid.github.io/) failed waiting for process: exit status 1
Error: looks like "https://kiwigrid.github.io/" is not a valid chart repository or cannot be reached: failed to fetch https://kiwigrid.github.io/index.yaml : 404 Not Found

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No chart changes detected.
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failed linting charts: failed adding repo: kiwigrid=[https://kiwigrid.github.io:](https://kiwigrid.github.io/) failed waiting for process: exit status 1
Error: Process completed with exit code 1.