[FIX] web: make list view table borders visible in Firefox

## Steps to reproduce
* Using Firefox, Go to Accounting > Invoices > create a new invoice.
* Add a line to the invoice and remove the label.

You should see that there's no indication that the label field is
required. (It works well in Chrome)

## Cause
This is happening because the table borders (that become red when a
field fails validation) are not displayed in Firefox.

opw-3040299

closes odoo/odoo#107564

X-original-commit: 74726c649fa5bddec30573c18acd11020302d093
Signed-off-by: Pierre Paridans (app) <app@odoo.com>
Signed-off-by: Nshimiyimana Serge Séna (sesn) <sesn@odoo.com>

addons/web/static/src/legacy/scss/list_view.scss

@@ -272,7 +272,6 @@
         }
 
         .o_data_row.o_selected_row > .o_data_cell:not(.o_readonly_modifier):not(.o_invisible_modifier) {
-            position: relative; // for o_field_translate
             &:not(.o_handle_cell) {
                 background-color: $o-view-background-color;
             }