Minor 5.56x45mm ammo belt [U]nload bug

[thepotate0]

Describe the bug

When [U]nloading a 5.56x45mm ammo belt, an error relating to removing an item from something that does not have the item is produced.

Steps To Reproduce

Steps to reproduce the behavior:

1. Create an ammo belt with ammunition loaded
2. Use [U] to unload things on the ground, and select the belt
3. Error is shown, however you still receive appropriate linkages and rounds

Expected behavior

The belt should be unloading into linkages and rounds without producing the error.

Screenshots

Versions and configuration

• OS: Windows
  • OS Version: Windows 10.0 1903
• Game Version: 0.D-11044-g605409a [64-bit]
• Graphics Version: Tiles
• Mods loaded: [
  Dark Days Ahead [dda],
  Disable NPC Needs [no_npc_food],
  Craftable Gun Pack [craftgp],
  Makeshift Items Mod [makeshift],
  Medieval and Historic Classes and Shields [Medieval_Stuff],
  More Survival Tools [More_Survival_Tools],
  More Locations [more_locations],
  Fuji's More Buildings [FujiStruct],
  Vehicle Additions Pack [blazemod],
  Tanks and Other Vehicles [Tanks],
  Folding Parts pack [deoxymod]
  ]

Additional context

N/A

[Night-Pryanik]

Duplicate of #35368.