Add tricopter picture to wizard

The tricopter picture needs to be added to the wizard, as it is currently for the normal firmware loading option. At the moment you have to click on the quadcopter to get the tricopter layout on the wizard, which is confusing for those not in the know.

Start by locating the wizard's normal firmware-loading option and the quadcopter/tricopter layout selection in the Mission Planner codebase. Identify where the wizard images and layout choices are defined, then verify that the tricopter picture is shown directly for the tricopter option rather than requiring the quadcopter choice.

Written by the indexing model from the issue text.