Update mongodb.md (#1293)

Remove references to --direct-connection which was not implemented

Co-authored-by: Catalina A <[email protected]>

docs/setting-up/client/mongodb.md

@@ -203,7 +203,6 @@ When successful, PMM Client will print `MongoDB Service added` with the service'
 !!! hint alert alert-success "Tips"
     - When adding nodes to a sharded cluster, ensure to add each node separately using the `--cluster mycluster` option. This allows the [MongoDB Cluster Summary](../../details/dashboards/dashboard-mongodb-cluster-summary.md) dashboard to populate correctly. 
     - You can also use the `--replication-set` option to specify a replication set, altough they are automatically detected. For instance, you can use `--replication-set config` for your config servers; `--replication-set rs1` for your servers in the first replica set, `--replication-set rs2` for your servers in the second replica set, and so on.
-    - When connecting to an Atlas instance, keep in mind that direct connections are not supported. Make sure to use the `--direct-connection=false` option with `pmm-admin`. Otherwise, replicaset status functionality will not work as expected, and the MongoDB Overview dashboard widget will show invalid values.
 
 ### Examples