fix: Fixes issue with cached static gump strings. Fixes bad gump colors (#1771)

### Summary
- Fixes an issue that causes CUO to crash due to bad string caching in static gumps
- Fixes wrong/bad 16bit html gump hues.
- Moves `C16232` (16-bit to 32-bit) and `C32216` (32-bit to 16-bit) to Utility class for broader use.

TODO:
- Some gumps have different 32bit (for string content) vs 16bit (for localized content) strings. Does this matter?

Projects/UOContent/Engines/ML Quests/Objectives/GainSkillObjective.cs

@@ -73,7 +73,7 @@ namespace Server.Engines.MLQuests.Objectives
             var skillLabel = AosSkillBonuses.GetLabel(Skill);
             var args = $"#{skillLabel}\t{ThresholdFixed / 10.0:0.#}";
 
-            g.AddHtmlLocalized(98, y, 312, 16, 1077485, args, 0x15F90); // Increase ~1_SKILL~ to ~2_VALUE~
+            g.AddHtmlLocalized(98, y, 312, 16, 1077485, args, 0x5F90); // Increase ~1_SKILL~ to ~2_VALUE~
             y += 16;
         }
 
@@ -158,7 +158,7 @@ namespace Server.Engines.MLQuests.Objectives
 
             if (IsCompleted())
             {
-                g.AddHtmlLocalized(113, y, 312, 20, 1055121, 0xFFFFFF); // Complete
+                g.AddHtmlLocalized(113, y, 312, 20, 1055121, 0x7FFF); // Complete
                 y += 16;
             }
         }