Before this commit, the `BlockUI` component from
the web module was not rendered properly.
The reason for this is that after PR #83811 was merged,
the css from `web/static/src/core/ui/block_ui.scss`
was replaced with non-semantic Bootstrap css classes
(e.g. .d-flex, .justify-content-center). Those css
classes were inaccessible to PoS frontend, because
the `point_of_sale` module does not load Bootstrap
code (a design decision).
In this commit, we restore the proper rendering
of the `BlockUI` component both for the "frontend"
of the PoS App.
task-2924335
X-original-commit: 29cbeae90790ff503167b053ec6d9e221a82434e
Part-of: odoo/odoo#97730
Eleftherios Kritsotakis
7bc582d1cf