### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

Prometheus litellm_total_users and litellm_teams_count metrics cannot be enabled when metrics are explicitly configured.

Explicit metric config configuration is opt-in so metric names need listed for them to be exposed.

Current metric validation does not support the listing of litellm_total_users & litellm_teams_count and will return and error if configured.

### Steps to Reproduce

1. litellm_settings: prometheus_metrics_config: - group: "my_metrics" metrics: - litellm_proxy_total_requests_metric

Will cause other metrics to disappear. 2. litellm_settings: prometheus_metrics_config: - group: "my_metrics" metrics: - litellm_proxy_total_requests_metric - litellm_total_users (or litellm_total_users_metric) Will cause a validation error. e.g. ``` ╭──────────────────────────────────────────────────────────────────────────────╮ │ 🚨🚨 Configuration Validation Errors │ ╰─────────────────────────────────────────────────────────────────────────…