MM-34983: Remove check for number of data sources (#17431)

In case of Aurora databases, a single endpoint
might load balance between multiple replicas.
In that case, this check is incorrect. Therefore,
we remove it

https://mattermost.atlassian.net/browse/MM-34983

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/config.go

@@ -3396,10 +3396,6 @@ func (s *SqlSettings) isValid() *AppError {
 		return NewAppError("Config.IsValid", "model.config.is_valid.sql_max_conn.app_error", nil, "", http.StatusBadRequest)
 	}
 
-	if len(s.ReplicaLagSettings) > len(s.DataSourceReplicas) {
-		return NewAppError("Config.IsValid", "model.config.is_valid.replica_mismatch.app_error", nil, "", http.StatusBadRequest)
-	}
-
 	return nil
 }