UI: Popover Button Padding for Arrow

Currently UI_BTYPE_POPOVER with icon and without text will get enough
extra padding to fit a downward arrow, only if in a header region. This
PR allows it to get the same padding in other areas when "force_menu"
is true.

Pull Request: https://projects.blender.org/blender/blender/pulls/119181

source/blender/editors/interface/interface_layout.cc

@@ -2994,7 +2994,8 @@ static uiBut *ui_item_menu(uiLayout *layout,
   }
 
   uiTextIconPadFactor pad_factor = ui_text_pad_compact;
-  if (layout->root->type == UI_LAYOUT_HEADER) { /* Ugly! */
+  /* Ugly! Extra padding in specific circumstances. */
+  if (layout->root->type == UI_LAYOUT_HEADER || force_menu) {
     if (icon == ICON_NONE && force_menu) {
       /* pass */
     }