[FIX] web_editor, website: fix menu colors in table of content

Before this commit, the colors of the navbar in the table of content
menu were not adapted to the color combinations system. With navbar in
top position, the background and the colors of the links were using the
same color.

After this commit, the colors of the list-group-item links are also
adapted with color combinations.

task-2312878

closes odoo/odoo#58601

X-original-commit: a0dc17676c570887773854243bcb8cd8823359d5
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>