Modify the API Client credential and configuration for the associated API Client.

To add or modify IP filtering:
1) First retrieve the clientId using GET /onpremagents/{id}/apicreds
2) Then use this PUT endpoint with the clientId to update ipFilterOp and ipFilters. Both fields should be set together.
3) To remove IP filtering, set both to null. Changes take effect immediately.

Note: IP filtering cannot be configured during agent creation and must be added after creation using this endpoint. Bridge agent API clients do not appear in the standard 'Secure > API clients' UI section.

Entitlements:
- manageExternalAgents (Manage external Agent configurations)