DX Unified Infrastructure Management

I understand there is a mongodb_monitor probe that is capable of monitoring the mongodb.
But, just as an alternative has anyone tried to integrate mongodb opsmanager with UIM wherein the OpsManager utilises the Webhook for notifying alerts.

Whether it has capable of sending SNMP traps ? If means you can do with snmptd probe

That would have been my guess but it seems it can't send traps

My perspective is UIM not MongoDB so perhaps you can supply some specific details on how OpsManager makes the data available.

Just for reference here are the metrics the probe supports:

mongodb_monitor Metrics - CA Unified Infrastructure Management Probes - CA Technologies Documentation 

So, the OpsManager manages the alerting of all the mongodb connected to it

It can make available all the alerts with below methods available at OpsManager
WebHook: Sends an HTTP POST request to an endpoint for programmatic processing. The request body contains a JSON document that uses the same format as the Ops Manager API Alerts resource. This option is available only if you have configured Webhook settings on the Group Settings page.

More info on Alerts — MongoDB Ops Manager 3.6