Cargos exploration drones are full when they aren't full

[MonkestationIssueBot]

Reporting client info: Client Information:
BYOND:515.1647
Key:englishscotsman

Round ID:

8941

Testmerges:

• [DNM] Aneri except I redid the branch again
• Heliostation from fulp
• 3D printed guns.
• [BOUNTY] Port Skyrat's feature to be able to play the character we want in a ghost role (using character loadouts
• Revert "Fixes and balances some problems with satyrs (#4712)"
• [DNM] Icon and filter optimization stuff
• The shot gun
• Lead Poisoning Station: A bizarro station for use on monke
• [Code Bounty] Makes IPC's spew ion laws for a little while after being emagged
• Update Yarn (3.3.1 -> 4.5.1) and Node (20.13.0 -> 22.11.0)
• Update SpacemanDMM and rust-g
• Various internal mechcomp fixes
• Update Medical cyborgs.
• [DNM] The Derelict / KS13 Engineering Update
• Even more various fixes
• Phobia regex should not be a global expression
• Phobias should not prevent forced says
• Spess.tv
• Fixes issue #4664 by moving up sleep infliction in order

Reproduction:

At being nearly full, at 5 slots, they'll throw away any items when they have 5 and would put it to 6. they can clearly use their 6 slots when putting items in the drone manually.