[FIX] web_editor: updating mobile view layout

Before this commit:

On mobile view the toolbar icon gets hidden, which it should not.

After this commit:

Now the toolbar items are flexed and wrapped.

Task-2752096

closes odoo/odoo#111849

X-original-commit: d3e6797f
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>