Fix missing animation decorators for pointer buttons

Also, remove manually placed decorator for vertex groups in modifiers. This was
only needed because of this bug, and the layout was slightly misaligned.

source/blender/editors/interface/interface_layout.c

@@ -1054,7 +1054,7 @@ static uiBut *ui_item_with_label(uiLayout *layout,
 
 #ifdef UI_PROP_DECORATE
   /* Only for alignment. */
-  if (layout->item.flag & UI_ITEM_PROP_SEP) {
+  if (use_prop_sep) { /* Flag may have been unset meanwhile. */
     if ((layout->item.flag & UI_ITEM_PROP_DECORATE) &&
         (layout->item.flag & UI_ITEM_PROP_DECORATE_NO_PAD) == 0) {
       uiItemL(layout_prop_decorate ? layout_prop_decorate : sub, NULL, ICON_BLANK1);

source/blender/modifiers/intern/MOD_ui_common.c

@@ -172,9 +172,6 @@ void modifier_vgroup_ui(uiLayout *layout,
     uiLayoutSetPropDecorate(sub, false);
     uiItemR(sub, ptr, invert_vgroup_prop, 0, "", ICON_ARROW_LEFTRIGHT);
   }
-  if (uiLayoutGetPropDecorate(layout)) {
-    uiItemL(row, "", ICON_BLANK1);
-  }
 }
 
 /**