[FIX] web: fix kanban_image when called for a different record

The issue is manifesting for example in the Contact kanban view where the
company image should be displayed in small. Before this fix, the person image
was displayed twice instead.

Following PR #30881 and commit: f78b7a76

The fix introduced by the above commit highlighted another issue with the
method: if the `model` and `id` given in parameter are different than the
current record, the method returned the url for the current record instead of
the requested record.

To fix the issue, we return the `raw_value` only if the requested record is the
current record. Otherwise, we return the manually built url.

PR: #31842

Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>