Getting tab order programmatically

**Is your feature request related to a problem? Please describe.**
Currently, there is no way of getting the order of the tabs in a tab bar. Getting the children of the tab bar only outputs the order in which the children/tabs were created.

**Describe the solution you'd like**
Having a new function to either get the order of the tabs in the tab bar, or having get_item_info have the order included.

**Additional context**
Currently, it is possible to get the get_item_rect_max and deduct the order using where the actual tab is drawn.
This breaks when the UI is still staged and not yet drawn and will always output 0 0 in that case.