Fix Service Ping destination host

What does this MR do?

It modifies the Service Ping docs to show the correct destination for usage metrics.

The correct IP address is nowadays 35.190.167.255, but using the hostname instead would accommodate for IP address changes in the future.

Related issues

Author's checklist

• Optional. Consider taking the GitLab Technical Writing Fundamentals course.
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• ~"frontend"
• ~"backend"
• ~"type::bug"
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These labels cause the MR to be added to code verification QA issues.

Reviewer's checklist

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If you aren't sure which tech writer to ask, use roulette or ask in the #docs Slack channel.

• If the content requires it, ensure the information is reviewed by a subject matter expert.
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    • If the content still needs to be edited for topic types, you can create a follow-up issue with the docs-technical-debt label.
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