Choice Set Manager uniqueness doesn't take into account loaded cells

[joeljfischer]

Bug Report

In the choice set manager, cells that are already loaded on the module need to be taken into account for uniqueness. Currently, it does not, which can lead to clashes when trying to present new cells.

This was found in unit tests and was not attempted to replicate on the head unit.

Reproduction Steps

1. Using a sub-7.1.0 module
2. Load a cell on the head unit
3. Attempt to load a unique cell with identical primary text

Expected Behavior

The new cell has an identifier appended to it

Observed Behavior

The cell fails to load

OS & Version Information

• iOS Version: n/a
• SDL iOS Version: v7.3.0-develop
• Testing Against: Unit test

Test Case, Sample Code, and / or Example App

n/a