[TMOG] Vendor has no option to Hide slot if you have no other tmogs. #

### Current Behaviour

Going to the vendor and wanting to hide your hat, or something and it is your FIRST hat. You have no option.

Same for other menus as far i can see shoulders, main hand and more.

### Expected Behaviour

Should have the Hide Slot available at all times. But it will only show if you got other options like here:

### Steps to reproduce the problem

Go to Tmog guy
Make sure ```.t i off``` is set as this only shows in the Gossip list.
Have no Tmogs on the account.
Try to hide a item.

### AC rev. hash/commit

https://github.com/chromiecraft/azerothcore-wotlk/commit/4974f0a3338e90d9a010b32bbbd01a062b525359

Start by reproducing the issue at the Tmog vendor with `.t i off` and no transmogs on the account, then trace the vendor's Gossip list handling for hat, shoulders, main hand, and other slots. Done means the Hide Slot option is available even when the character has no other transmog choices.

Written by the indexing model from the issue text.