Do not show tab list if only one terminal tab with multiple terminals

[isidorn]

Testing #122242

Currently you show the tab list if I have only one tab with multiple terminals.
I think this is wrong and by default we should only show the tab list if there are multiple terminal tabs.

Reason in the following setup space is particularly valuable

[Tyriar]

I don't think we should do this as the tab contains important information that would be hidden for the non-active terminal if we went this directyion. For example if the terminal is disconnected, task status (next iteration), etc. If this is a common setup I think the narrow tab view would be ideal.

If more people point this out we could expand terminal.integrated.tabs.hideForSingle but I wouldn't want to change this default.

[isidorn]

Makes sense to have this under a hideForSingle settings. Maybe a reason to have that setting name more general and make it a string and not boolean.

[Tyriar]

Setting change part of this is moved to #122551