Clarify usage report requirements

[mjang]

Is your feature request related to a problem? Please describe

Apparent lack of clarity in https://docs.nginx.com/nginx-instance-manager/disconnected/report-usage-disconnected-deployment/

Discussion in Slack: https://f5.slack.com/archives/C01FZ6BSZU0/p1743122210405379?thread_ts=1742830454.716019&cid=C01FZ6BSZU0

Describe the solution you'd like

Suggested by Jake Newfield:

The frequency of submitting a usage report from NGINX Instance Manager to F5 is typically every 30 days. For details on how often you should submit a usage report, contact your F5 Customer Success Manager.

Describe alternatives you've considered

IMO the current overview in https://docs.nginx.com/nginx-instance-manager/disconnected/report-usage-disconnected-deployment/ is neither clear nor concise.