Fix include_optional_metrics_in_service_ping during migration to 16.10

What does this MR do and why?

This backports !147874 (merged) to 16-10-stable-ee.

When LDAP is enabled, the migration to 16.10 can fail due to a stale ApplicationSetting not having include_optional_metrics_in_service_ping: #451449 (closed)

MR acceptance checklist

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• This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
• The MR that fixed the bug on the default branch has been deployed to GitLab.com (not applicable for documentation or spec changes).
• This MR has a severity label assigned (if applicable).
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• This MR has been approved by a maintainer (only one approval is required).
• Ensure the e2e:package-and-test-ee job has either succeeded or been approved by a Software Engineer in Test.

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