menu/rgui: don't wipe framebuffer behind info popup

rgui_render() was filling the entire framebuffer with bg_dark_color
before drawing the info messagebox, which erased the menu underneath
and left the popup floating against an empty background.

The messagebox already paints its own opaque background, border, and
drop shadow within its footprint, so the full-screen fill served no
purpose other than destroying the menu render that had just been
composed above it. Drop it; the popup now appears on top of the
visible menu as intended.

Author: LibretroAdmin

menu/drivers/rgui.c

@@ -5919,13 +5919,8 @@ static void rgui_render(void *data, unsigned width, unsigned height,
 
    if (*rgui->msgbox)
    {
-      /* Draw background */
-      rgui_fill_rect(rgui->frame_buf.data, fb_width, fb_height,
-            0, 0, fb_width, fb_height,
-            rgui->colors.bg_dark_color,
-            rgui->colors.bg_dark_color,
-            (rgui->flags & RGUI_FLAG_BG_THICKNESS) ? true : false);
-
+      /* Draw popup directly on top of the menu; the messagebox
+       * paints its own opaque background within its footprint. */
       rgui_render_messagebox(rgui, rgui->msgbox, fb_width, fb_height);
       rgui->msgbox[0]    = '\0';
       rgui->flags       |=  RGUI_FLAG_FORCE_REDRAW;