Tether gun fixes (#8129)

Content.Shared/Audio/AmbientSoundComponent.cs

@@ -12,7 +12,7 @@ namespace Content.Shared.Audio
         [DataField("enabled")]
         public bool Enabled { get; set; } = true;
 
-        [DataField("sound", required: true)]
+        [DataField("sound", required: true), ViewVariables(VVAccess.ReadWrite)]
         public SoundSpecifier Sound = default!;
 
         /// <summary>

Content.Shared/Weapons/Ranged/SharedTetherGunSystem.cs

@@ -23,3 +23,12 @@ public sealed class TetherMoveEvent : EntityEventArgs
 {
     public MapCoordinates Coordinates;
 }
+
+/// <summary>
+/// Client can't know the tether's <see cref="EntityUid"/> in advance so needs to be told about it for prediction.
+/// </summary>
+[Serializable, NetSerializable]
+public sealed class PredictTetherEvent : EntityEventArgs
+{
+    public EntityUid Entity;
+}