Mission Abandonment Confirmation (#3707)

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## About The Pull Request

Fixes #3700 by requiring a confirmation pop up to give up on missions.
Minor QoL.

## Why It's Good For The Game

Prevents people from accidentally abandoning missions when they didn't
mean to, and provides more time to reconsider it.

## Changelog

:cl:
add: Added a confirmation pop up for abandoning missions.
/:cl:

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code/modules/cargo/console.dm

@@ -255,7 +255,7 @@
 			else if(mission.servant == ship)
 				if(mission.can_complete())
 					mission.turn_in()
-				else
+				else if(tgui_alert(usr, "Give up on [mission]?", src, list("Yes", "No")) == "Yes")
 					mission.give_up()
 				return TRUE