[enterprise-4.15] OBSDOCS-67: Add info that monitoring API routes are not available in web browsers

[openshift-cherrypick-robot]

This is an automated cherry-pick of #73397

/assign bburt-rh

[openshift-ci-robot]

@openshift-cherrypick-robot: Ignoring requests to cherry-pick non-bug issues: OBSDOCS-67

In response to this:

This is an automated cherry-pick of #73397

/assign bburt-rh

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[ocpdocs-previewbot]

🤖 Thu Mar 21 19:38:34 - Prow CI generated the docs preview:
https://73582--ocpdocs-pr.netlify.app

[openshift-ci]

@openshift-cherrypick-robot: all tests passed!

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