When performing an import-compatible export, m2m values would be
exported as a record per cell unless the `id` subfield was the first
to be exported. Which is not the case when using the export UI (as it
always adds the field itself before any subfield). This would make the
m2m not actually export-compatible in most cases.
* export m2m "display name" in an import compatible format as well
* re-prioritise exporting xids when there are multiple m2m exports in
import-compatible mode
* never fall back on the o2m / non-import-compatible m2m path for m2ms
in import-compatible mode
Note: if multiple m2m fields are specified only one of them gets filled.
Task 2065428
closesodoo/odoo#37407
Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>
Co-authored-by: Ravi Singh <ras@odoo.com>
Co-authored-by: Mohammed Shekha <msh@odoo.com>
Co-authored-by: Xavier Morel <xmo@odoo.com>
