libgimpwidgets: set a minimum width on GimpColorProfileComboBox

so ellipsation doesn't shrink the entire text away in narrow dialogs.

libgimpwidgets/gimpcolorprofilecombobox.c

@@ -139,6 +139,7 @@ gimp_color_profile_combo_box_init (GimpColorProfileComboBox *combo_box)
   GtkCellRenderer *cell = gtk_cell_renderer_text_new ();
 
   g_object_set (cell,
+                "width-chars", 42,
                 "ellipsize",   PANGO_ELLIPSIZE_END,
                 NULL);