In commit [1], a check was added to see if a media is editable in order
to prevent its edition if it is not the case. However, this also had as
effect to block the edition of some grid images. Indeed, as the columns
in grid mode containing only an image have their `contenteditable`
property set to `false`, the images don't pass the check because their
parent is therefore not editable.
This commit removes the `contenteditable` property from these columns
in order to make their images pass the check and therefore allow their
edition.
Tests are also added, ensuring that these grid images can be correctly
replaced.
[1]: https://github.com/odoo/odoo/commit/ddade4346347266b7f699d05865578dc96e2bf98
opw-3028116
Fixes#103234closesodoo/odoo#104899
X-original-commit: d8c374e3e6b31bf88aa42952aadf3379936f7600
Related: odoo/design-themes#617
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>