Unable to add underbarrel weapon to weapons in career mode

[DarbyDay]

Describe the bug
When attempting to add an underbarrel weapon to any weapon the message "You must first select a Weapon to add an Accessory to." appears despite the weapon being selected. This issue does not occur in chargen mode.

To Reproduce
Steps to reproduce the behavior:

1. Create a character and save them after checking the "Mark character as Created" box
2. Click on street gear
3. Click on weapons
4. Add a weapon
5. Attempt to add an underbarrel weapon by right-clicking on the weapon
6. See error

Expected behavior
A list of valid underbarrel weapons should appear as it does in chargen mode.

Screenshots

Character File
Sample character file with issue present attached.
Firearms_McGraw (career).zip

Desktop (please complete the following information):

• OS: Windows 10
• Version 10.0.19043 Build 19043

Additional context

• Chummer version 5.225.0
• Character settings file attached:
  default.zip

[DelnarErsike]

That underbarrel weapon selection dialog kind of shouldn't even be there and is instead just a remnant of SR4e rules. I'll mark this as a C# bug, but we honestly should just remove that entire menu to avoid confusion.

[LNSmith458]

Related to #5056 , it would need to be fixed first before removing the menu.