[FIX] web_editor: fix original not being properly set when cropping

Previously, if you opened the cropper on an already cropped image, it
would load the crop data for that image. If you then changed the image
and cropped that new image, it would keep most of the metadata of the
previous image when saving, causing any subsequent crop to show the
previous original image instead of the current one.

This commit fixes that by removing all crop-related jQuery data from the
image, so it's considered a fresh crop and a new attachment is created.

closes odoo/odoo#49375

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>