Add FORCEDROP_CONDITIONAL and SMARTGUNNER_BACKPACK_OVERRIDE to bitfie…

…lds (#6881)

# About the pull request

This PR is a followup to #6150
and #5914 that added new
flags_item flags but not to the bitfields

# Explain why it's good for the game

Allows the VV to allow editing and displaying these flags correctly.

# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>


![image](https://github.com/user-attachments/assets/3b292717-c48a-4d22-89ef-c4a549db9a1c)

</details>


# Changelog
:cl: Drathek
code: Added missing bitfields for flags_item to VV
/:cl:

code/_globalvars/bitfields.dm

@@ -177,6 +177,8 @@ DEFINE_BITFIELD(flags_item, list(
 	"CAN_DIG_SHRAPNEL" = CAN_DIG_SHRAPNEL,
 	"ANIMATED_SURGICAL_TOOL" = ANIMATED_SURGICAL_TOOL,
 	"IGNITING_ITEM" = IGNITING_ITEM,
+	"FORCEDROP_CONDITIONAL" = FORCEDROP_CONDITIONAL,
+	"SMARTGUNNER_BACKPACK_OVERRIDE" = SMARTGUNNER_BACKPACK_OVERRIDE,
 ))
 
 DEFINE_BITFIELD(flags_inv_hide, list(