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.Server/Forensics/Systems/ForensicScannerSystem.cs

@@ -16,6 +16,7 @@ using Robust.Shared.Audio;
 using Robust.Shared.Player;
 using Robust.Shared.Timing;
 using Content.Server.Chemistry.Containers.EntitySystems;
+using Robust.Shared.Prototypes;
 // todo: remove this stinky LINQy
 
 namespace Content.Server.Forensics
@@ -33,6 +34,8 @@ namespace Content.Server.Forensics
         [Dependency] private readonly ForensicsSystem _forensicsSystem = default!;
         [Dependency] private readonly TagSystem _tag = default!;
 
+        private static readonly ProtoId<TagPrototype> DNASolutionScannableTag = "DNASolutionScannable";
+
         public override void Initialize()
         {
             base.Initialize();
@@ -86,7 +89,7 @@ namespace Content.Server.Forensics
                     scanner.Residues = forensics.Residues.ToList();
                 }
 
-                if (_tag.HasTag(args.Args.Target.Value, "DNASolutionScannable"))
+                if (_tag.HasTag(args.Args.Target.Value, DNASolutionScannableTag))
                 {
                     scanner.SolutionDNAs = _forensicsSystem.GetSolutionsDNA(args.Args.Target.Value);
                 } else