Allow multiple protocols in protocol listener health check

[the-mikedavis]

Proposed Changes

This covers the optional part of #13782: updating GET /api/health/checks/protocol-listener/{protocol} to accept multiple protocols, comma-separated. The check only returns 200 OK when all of the request protocols have listeners available.

Connects #13782.

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• Bug fix (non-breaking change which fixes issue #NNNN)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• Documentation improvements (corrections, new content, etc)
• Cosmetic change (whitespace, formatting, etc)
• Build system and/or CI

NOTE: the field in the error response missing is updated to a list. I'm not sure if we should consider this as a breaking change or not.

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Further Comments

This PR also adds a commit which changes the helper used to look for active listeners from rabbit_networking:active_listeners/0 to rabbit_networking:node_listeners(node()) - this eliminates some unnecessary RPC calls. It's unrelated to the feature part of this change.

[michaelklishin]

@the-mikedavis thank you, I'm on it.

FYI, the HTTP API reference was moved to the website. It's fine to update the bits in this repo, of course, but the plan is to eventually only have a website link.

[michaelklishin]

rabbitmqadmin should be covered by this enum variant, not sure if it's worth the time introducing another one for multiple protocols. Probably not.

[the-mikedavis]

Ah I see that in the website repo now. I'll add the updates for this and #13872 (and the future health-check PRs) in some PRs to the website repo too 👍