Power cell overlay now updates when exiting an object's contents (#85079)

## About The Pull Request
The charge indicator overlay on power cells is now properly updated when
the cell is charged/discharged. Before, you could use a power cell until
it's empty and the overlay wouldn't change at all.
## Why It's Good For The Game
The overlay is there to indicate the charge of the cell. It should work.
## Changelog
🆑
fix: The charge indicators on power cells now work properly.
code: Removed some now redundant power cell appearance updates
/🆑

---------

Co-authored-by: jimmyl <70376633+mc-oofert@users.noreply.github.com>

code/modules/mob/living/basic/bots/_bots.dm

@@ -517,7 +517,6 @@ GLOBAL_LIST_INIT(command_strings, list(
 	if(istype(item_to_drop, /obj/item/stock_parts/power_store/cell))
 		var/obj/item/stock_parts/power_store/cell/dropped_cell = item_to_drop
 		dropped_cell.charge = 0
-		dropped_cell.update_appearance()
 		return
 
 	if(istype(item_to_drop, /obj/item/storage))