[IMP] web_responsive: Remove unnecessary calendar optimisation

Removed the optimisation of hiding the week number at a certain size
for consistency with the responsive design of Odoo enterprise. It is a
non-functional optimisation as it hides useful information that hardly
takes up any space. It also causes incompatibilities in the design with
extensions that do not take into account these specific changes.

TT54811

web_responsive/static/src/legacy/scss/web_responsive.scss

@@ -24,12 +24,6 @@ $chatter_zone_width: 35% !important;
         height: 35px;
     }
     .o_calendar_widget {
-        .fc-dayGridMonth-view {
-            .fc-week-number {
-                display: none;
-            }
-        }
-
         .fc-timeGridDay-view {
             .fc-day-header {
                 vertical-align: middle;