It is possible that the L-Pack output could be switched from the standard configuration with a balanced mono output consisting of the two microphone signals summed within the device, to an unbalanced stereo out with separate microphone signals. The same 3-conductor XLR out can be used for either configuration. However, that functionality is not apparent from the photos nor Thomann's very limited description of it. Unfortunately there is no link to a user manual, and a google search turned up nothing.
The cable you linked would work. The issue isn't the cable but if the L-pack can output an unbalanced stereo signal instead of a balanced mono signal.
That cable can transmit either two unbalanced signals (stereo), or one balanced signal (mono). Either way there are three conductors. In balanced mode the three are designated: shield, signal +, and signal -. In unbalanced mode the three are designated: shared signal ground, channel 1 signal +, and channel 2 signal +.