In this ticket, we will do the following things:

• Change the DbClient runCommandWithTarget to take in DatabaseName object.
• In runCommandWithTarget function, we should create opMsgRquest with "$tenant" if our project feature flag is enabled.
• Refactor the DbClient functions which have "appendDollarTenant" as parameter. This parameter is used by bench run to indicate db client should always append "$tenant" without caring our project's feature flag.