Fix coords monitor in replays (#29512)

The F3 coords manager is blocked if you're not an admin. This check happened even when playing a replay, where you actually aren't. There's now a check to make sure you are actually server-connected-to-game before running the logic.

Also moved it to a manager because this *shouldn't be a bloody entity system in the first place*.

Content.Client/DebugMon/DebugMonitorManager.cs

@@ -0,0 +1,28 @@
+using Content.Client.Administration.Managers;
+using Content.Shared.CCVar;
+using Robust.Client;
+using Robust.Client.UserInterface;
+using Robust.Shared.Configuration;
+
+namespace Content.Client.DebugMon;
+
+/// <summary>
+/// This handles preventing certain debug monitors from being usable by non-admins.
+/// </summary>
+internal sealed class DebugMonitorManager
+{
+    [Dependency] private readonly IConfigurationManager _cfg = default!;
+    [Dependency] private readonly IClientAdminManager _admin = default!;
+    [Dependency] private readonly IUserInterfaceManager _userInterface = default!;
+    [Dependency] private readonly IBaseClient _baseClient = default!;
+
+    public void FrameUpdate()
+    {
+        if (_baseClient.RunLevel == ClientRunLevel.InGame
+            && !_admin.IsActive()
+            && _cfg.GetCVar(CCVars.DebugCoordinatesAdminOnly))
+        {
+            _userInterface.DebugMonitors.SetMonitor(DebugMonitor.Coords, false);
+        }
+    }
+}