fix: make helm use grpc for compactor address

[rurod]

What this PR does / why we need it:
Align the computation logic of the compactor address with how other address are computed.
Moreover, it makes use of grpc, as according to the Loki codebase, it's the preferred way :
https://github.com/grafana/loki/blob/46b2271aacd26734979667da61d5c9d24a8efb2b/pkg/loki/modules.go#L1256C1-L1274C2

Which issue(s) this PR fixes:
Kind of fixes #17100, as using the full hostname of the service rather than the short name helps comply with the no_proxy instruction, even if not mandatory

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
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