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/Ui/SettingsTabs/ThemeAndLayout.cs

@@ -78,7 +78,7 @@ internal sealed class ThemeAndLayout : ISettingsTab
             {
                 var dir = Path.Combine(Plugin.Interface.ConfigDirectory.FullName, "themes");
                 Directory.CreateDirectory(dir);
-                Dalamud.Utility.Util.OpenLink(dir);
+                Plugin.PlatformUtil.OpenLink(dir);
             }
 
             ImGui.SameLine();