Fix action numbers (/handle UI default theme update) (#15840)

Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Client/UserInterface/Systems/Actions/Controls/ActionButton.cs

@@ -158,6 +158,7 @@ public sealed class ActionButton : Control
 
     protected override void OnThemeUpdated()
     {
+        base.OnThemeUpdated();
         Button.Texture = Theme.ResolveTexture("SlotBackground");
         Label.FontColorOverride = Theme.ResolveColorOrSpecified("whiteText");
     }