Limit "Die a glorious death" objective to one traitor per round. (#1819)

First commit

Author: beck-thompson

Resources/Prototypes/Objectives/traitor.yml

@@ -66,6 +66,10 @@
       - EscapeShuttleCondition
       - StealCondition
   - type: DieCondition
+  # The game turns into a massive suicide pact if enough of the traitors have it. Not fun for traitors or security!
+  # Giving it a limit keeps the objective unique and interesting without being overdone.
+  - type: ObjectiveLimit # Delta-V
+    limit: 1 # Delta-V
 
 #- type: entity
 #  parent: [BaseTraitorObjective, BaseLivingObjective]