[FIX] web: appropriate color theme

Do not mix Community and Enterprise color themes. Moreover, increase the
contrast of the control panel for better readability.

closes odoo/odoo#27502

addons/web/static/src/scss/primary_variables.scss

@@ -13,7 +13,7 @@ $o-community-color: #7C7BAD;
 $o-enterprise-color: #875A7B;
 $o-enterprise-primary-color: #00A09D;
 
-$o-brand-odoo: $o-enterprise-color;
+$o-brand-odoo: $o-community-color;
 $o-brand-primary: $o-community-color;
 
 $o-brand-secondary: #f0eeee;

addons/web/static/src/scss/search_view_extra.scss

@@ -6,10 +6,10 @@
 
     .o_searchview_facet {
         border: 1px solid gray('600');
-        background: lighten(gray('600'), 35%);
+        background: $o-brand-lightsecondary;
 
         .o_searchview_facet_label {
-            background-color: gray('600');
+            background-color: $o-brand-odoo;
         }
 
         .o_facet_remove {

addons/web/static/src/scss/secondary_variables.scss

@@ -1,5 +1,5 @@
 $o-webclient-background-color: desaturate($o-gray-100, 100%);
-$o-control-panel-background-color: desaturate(#e9ecef, 100%); // $gray-200 bts4 default
+$o-control-panel-background-color: $o-view-background-color;
 
 $o-list-footer-color: $o-main-text-color;
 $o-list-group-header-color: lighten($o-brand-lightsecondary, 10%);