[FIX] mrp: broken UI on Group By

1. Install [Manufacturing] on Apps
2. On [Settings]>[Manufacturing]
- toggle on [Work Orders], [Quality] & [Quality Worksheet]
3. Go to Manufacturing
- Work Centers (a.k.a WC) Overview should be visible
- if no W.C. by default, add from [Configuration]>[Work Centers]
- give tag to each W.C. (lengthy so as to test the overlap)
- click Manufacturing and [Group by] Tag (Custom)

affected branch: 16.0-master

opw-3177656

closes odoo/odoo#114303

Signed-off-by: William Henrotin (whe) <whe@odoo.com>
Signed-off-by: Lee, Hansun (hale) <hale@odoo.com>

addons/mrp/static/src/scss/mrp_workorder_kanban.scss

@@ -1,8 +1,5 @@
 .o_kanban_dashboard{
-    &.o_mrp_workorder_kanban .o_kanban_renderer {
-        .o_kanban_group:not(.o_column_folded) {
-            width: 400px + $o-kanban-group-padding;
-        }
+    &.o_mrp_workorder_kanban {
         .o_kanban_record {
             flex-basis: 40%;
             @include media-breakpoint-down(lg) {
@@ -22,12 +19,7 @@
             }
         }
     }
-    &.o_workcenter_kanban .o_kanban_renderer {
-        .o_kanban_group:not(.o_column_folded) {
-            width: 400px + $o-kanban-group-padding;
-        }
-        .o_kanban_record {
-            width: 400px;
-        }
+    &.o_workcenter_kanban {
+        --KanbanRecord-width: 400px;
     }
 }