During the Milk revamp, the dropdown items in the Dashboard's header
lost their horizontal margins. These have been put back by setting a gap
property to the parent.
When in the dashboard view under Sales > Product, the dropdowns had an
awkward spacing between them despite the fix. Another fix was to set
`w-100` to the `.o_field_tags` element. And finally a `.gap-1` is also
added to the latter to give its children some space when multiple tags
are selected.
It was noticed that some CSS, specifically the `.o-filter-value` class,
was not targeting anything. This has been fixed by moving the selector
into its correct parent element.
task-3326566
part of task-3326263
closesodoo/odoo#127010
X-original-commit: bd456bc89f896de6b3d8c040706dc02ab3799e6e
Signed-off-by: Lucas Lefèvre (lul) <lul@odoo.com>