In [1], in master, the `content` class is removed from the elements
with the `row` class in the Carousel snippet. This commit does the same
for the extension of Carousel in the "Clean" theme, to be consistent
with these changes.
[1]: https://github.com/odoo/odoo/pull/102696
task-3011192
closesodoo/design-themes#603
Related: odoo/odoo#102696
Signed-off-by: Vray Benjamin (bvr) <bvr@odoo.com>