Proposed title of this feature request

Enable `--web.enable-admin-api` for user-workload-monitoring

What is the nature and description of the request?

As an OpenShift admin, it's needed to have the option of enabling for the user-workload-monitoring prometheus the option `--web.enable-admin-api`

Why does the customer need this? (List the business requirements)

For being able to use `delete_series` [0] by an OpenShift admin under situations where some `serviceMonitors` configured collecting so many metrics leads to fill the storage.

Enabling it would allow to the Openshift admin to delete some series, at the same time that reviewing the service Monitors for adjusting them.

List any affected packages or components.

User Workload Monitoring Prometheus pods

[0] https://prometheus.io/docs/prometheus/latest/querying/api/#delete-series