refactor(ui): route OpenLink call-sites through Plugin.PlatformUtil (F12.1)

Ten Util.OpenLink call-sites across five files now go through the
IPlatformUtil indirection: WrapperUtil.TryOpenUri, the Settings Ko-Fi
buttons (x2), the Information tab (issues link plus media/upstream
links, x3), the Integrations tab (Honorific repo/author plus forge
discord, x3), and the ThemeAndLayout 'open themes folder' button.

A future addition to this pattern only needs to plug into IPlatformUtil
instead of touching Dalamud.Utility.Util directly.

HellionChat/Util/WrapperUtil.cs

@@ -22,7 +22,7 @@ public static class WrapperUtil
         try
         {
             Plugin.Log.Debug($"Opening URI {uri} in default browser");
-            Dalamud.Utility.Util.OpenLink(uri.ToString());
+            Plugin.PlatformUtil.OpenLink(uri.ToString());
         }
         catch (Exception ex)
         {