Fix T92293: Clipped labels for graph editor modifiers

While c7d94a7827 exposed this bug,
this was caused by a discrepancy in padding where labels would
have additional padding when drawing without emboss.
The padding made widget drawing behave as if the text took up more
room causing it to be clipped.

Now labels are considered the same width with/without emboss.

source/blender/editors/interface/interface_widgets.c

@@ -4632,6 +4632,9 @@ void ui_draw_but(const bContext *C, struct ARegion *region, uiStyle *style, uiBu
     switch (but->type) {
       case UI_BTYPE_LABEL:
         wt = widget_type(UI_WTYPE_ICON_LABEL);
+        if (!(but->flag & UI_HAS_ICON)) {
+          but->drawflag |= UI_BUT_NO_TEXT_PADDING;
+        }
         break;
       default:
         wt = widget_type(UI_WTYPE_ICON);