Extracts magic strings from Tag calls (#36305)

* Extracts magic strings from Tag calls

When #36281 gets merged, the `TagSystem` methods will all give warnings. Let's fix those warnings before they even happen!

* Adds missing libraries

* Remove not yet implemented TagSystem changes

* Fix tag spelling error

Genuinely surprised there was only 1!

* Styling and proper type changes

* Styling

Co-authored-by: Tayrtahn <tayrtahn@gmail.com>

---------

Co-authored-by: Tayrtahn <tayrtahn@gmail.com>

Content.Client/Verbs/VerbSystem.cs

@@ -16,6 +16,7 @@ using Robust.Client.State;
 using Robust.Shared.Configuration;
 using Robust.Shared.Containers;
 using Robust.Shared.Map;
+using Robust.Shared.Prototypes;
 using Robust.Shared.Utility;
 
 namespace Content.Client.Verbs
@@ -36,6 +37,8 @@ namespace Content.Client.Verbs
 
         private float _lookupSize;
 
+        private static readonly ProtoId<TagPrototype> HideContextMenuTag = "HideContextMenu";
+
         /// <summary>
         ///     These flags determine what entities the user can see on the context menu.
         /// </summary>
@@ -147,7 +150,7 @@ namespace Content.Client.Verbs
 
             for (var i = entities.Count - 1; i >= 0; i--)
             {
-                if (_tagSystem.HasTag(entities[i], "HideContextMenu"))
+                if (_tagSystem.HasTag(entities[i], HideContextMenuTag))
                     entities.RemoveSwap(i);
             }