[IMP] web: PivotRenderer, after BS5 cleanup

Commit preparatory to the introduction of dark-mode.

task-2710677

Part-of: odoo/odoo#102868

addons/web/static/src/views/pivot/pivot_renderer.xml

@@ -54,7 +54,7 @@
 
     <t t-name="web.PivotHeader" owl="1">
         <th
-            class="text-nowrap cursor-pointer fw-normal bg-100"
+            class="text-nowrap cursor-pointer fw-normal bg-100 user-select-none"
             t-att-colspan="isXAxis ? cell.width : undefined"
             t-att-rowspan="isXAxis ? cell.height : undefined"
             t-att-class="{
@@ -91,8 +91,8 @@
 
     <t t-name="web.PivotMeasure" owl="1">
         <th class="text-muted text-center text-nowrap fw-normal bg-100" t-att-colspan="cell.width" t-att-rowspan="cell.height" t-att-class="{
-                'o_pivot_origin_row cursor-pointer': cell.originIndexes,
-                'o_pivot_measure_row cursor-pointer': !cell.originIndexes,
+                'o_pivot_origin_row cursor-pointer user-select-none': cell.originIndexes,
+                'o_pivot_measure_row cursor-pointer user-select-none': !cell.originIndexes,
                 o_pivot_sort_order_asc: cell.order === 'asc',
                 o_pivot_sort_order_desc: cell.order === 'desc',
             }" t-on-click.prevent="() => this.onMeasureClick(cell)" t-on-mouseover="onMouseEnter" t-on-mouseout="onMouseLeave">

addons/web/static/src/views/pivot/pivot_view.scss

@@ -8,19 +8,10 @@
         @include o-hover-text-color($body-color, $o-main-link-color);
     }
 
-    // This can be removed after the migration to BS5.
-    th,
-    td {
-        border-width: $border-width;
-    }
-
     .o_pivot_measure_row,
     .o_pivot_origin_row,
     .o_pivot_header_cell_closed,
     .o_pivot_header_cell_opened {
-        // "user-select-none" class doesn't exist in BS 4.3.1, the user-select property
-        // could be replaced by a class after the migration to BS5
-        user-select: none;
         @include o-hover-text-color($body-color, $headings-color);
 
         &:hover {