Menu Manager won't send submenu cell images on RPC versions >= 5.0 && < 7.1

[crokita]

Bug Report

SDL added support for submenu cell images on v5.0 but didn't add an image field name until v7.1. When connecting to systems on or above v5.0 and below v7.1, we must send the submenu icon even if the image field name isn't there.

Reproduction Steps

1. Connect to a >= v5.0 && < v7.1 Core and HMI that supports submenu icons
2. Show a submenu cell with an image

Expected Behavior

The image appears

Observed Behavior

The image does not appear

Browser & Version Information

NodeJS and vanilla JS builds, not in any past releases.