[FIX] web_editor: stop suggesting shapes for model-related images

Those kind of images use a specific route (/web_editor/shape/...) to
be fetched. While waiting for a more complete solution to maybe handle
them for model-related images, this commit only allows their use for
images in views and HTML fields.

closes odoo/odoo#63682

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