use weighted random for ninja threats (#20469)

* change threats to be weighted random and a little cleanup

* ninja rule stores weighted random id for threats

* move threats out of the rule and into weighted random

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Co-authored-by: deltanedas <@deltanedas:kde.org>

Content.Server/GameTicking/Rules/Components/NinjaRuleComponent.cs

@@ -1,6 +1,8 @@
 using Content.Server.Ninja.Systems;
 using Content.Shared.Communications;
+using Content.Shared.Random;
 using Robust.Shared.Audio;
+using Robust.Shared.Prototypes;
 
 namespace Content.Server.GameTicking.Rules.Components;
 
@@ -15,7 +17,7 @@ public sealed partial class NinjaRuleComponent : Component
     /// List of threats that can be called in. Copied onto <see cref="CommsHackerComponent"/> when gloves are enabled.
     /// </summary>
     [DataField(required: true)]
-    public List<Threat> Threats = new();
+    public ProtoId<WeightedRandomPrototype> Threats = string.Empty;
 
     /// <summary>
     /// Sound played when making the player a ninja via antag control or ghost role