Selecting ID while adding new Input - UI consistency

[JimB40]

Is your feature request related to a problem?

Adding new Input will assign fist free ID.
All other lists have 2 step adding proces.

1. Tapping "+"
2. Selecting free slot (ID)

Describe the solution you'd like

After tapping "+" list of free slots should be displayed.

This will

1. unify adding item to the list across OS
2. Will make adding 2 step allowing to cancel process if "+" was selected by aciddent.

[pfeerick]

To clarify, what Robert means is to make the + at the bottom of the Inputs page the same as how it now behaves on the Mixes, LS and SF pages - whereby it shows the menu listing available slots.