Add chat.max_announcement_length cvar (#23571)

* Add announce message length to UI and make a cvar for it

* Update comm console server-side trim to use the cvar

* Rely on the new OnTextChanged event

Because OnKeyBindUp only works for keys that have binds

* Add a similar indicator to nukies' war declaration UI

* Remove message length indicators for now cuz it requires the engine update

* Rename cvar slightly

* Refactor duplicated code to a helper method

* Remove message trimming from *Window class as it's better to live in the BoundUserInterface where the other message handling happens

* Rename to chat.max_announcement_length

Content.Client/NukeOps/WarDeclaratorWindow.xaml.cs

@@ -2,7 +2,6 @@
 using Content.Shared.NukeOps;
 using Robust.Client.AutoGenerated;
 using Robust.Client.Graphics;
-using Robust.Client.UserInterface.Controls;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Client.UserInterface.XAML;
 using Robust.Shared.Timing;
@@ -27,7 +26,7 @@ public sealed partial class WarDeclaratorWindow : DefaultWindow
 
         _gameTiming = IoCManager.Resolve<IGameTiming>();
 
-        WarButton.OnPressed += ActivateWarDeclarator;
+        WarButton.OnPressed += (_) => OnActivated?.Invoke(Rope.Collapse(MessageEdit.TextRope));
 
         var loc = IoCManager.Resolve<ILocalizationManager>();
         MessageEdit.Placeholder = new Rope.Leaf(loc.GetString("war-declarator-message-placeholder"));
@@ -129,10 +128,4 @@ public sealed partial class WarDeclaratorWindow : DefaultWindow
                 return;
         }
     }
-
-    private void ActivateWarDeclarator(BaseButton.ButtonEventArgs obj)
-    {
-        var message = Rope.Collapse(MessageEdit.TextRope);
-        OnActivated?.Invoke(message);
-    }
 }