[FIX] website: increase footer home-icon readability

Ideally we should let background/text-color adapt to the current
color-preset. Since icons bg are forced to `$gray-100` though, this
commit will just increase readability allowing user's customization

task-2327741

closes odoo/odoo#59303

X-original-commit: 15ac3a2f08ed400ec5f64b40b7a8f5be04c46513
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

addons/website/views/website_templates.xml

@@ -1382,7 +1382,7 @@
                                 <a href="/website/social/linkedin" class="s_share_linkedin" target="_blank">
                                     <i class="fa fa-linkedin rounded-circle shadow-sm"/>
                                 </a>
-                                <a href="/" class="float-right">
+                                <a href="/" class="text-800 float-right">
                                     <i class="fa fa-home rounded-circle shadow-sm"/>
                                 </a>
                             </div>