spp_user_roles: role_ids_stored list-view workaround may be redundant after OCA base_user_role fix (#428)

[gonzalesedwin1123]

Follow-up from #508 / OCA server-backend #428, kept out of #508 deliberately (that PR was a CI-red hotfix and only renamed the xpath).

Background

spp_user_roles carries a stored Many2many on res.users:

# Stored version of base_user_role.user_role_ids for list view display
# The base_user_role One2many computed field doesn't display in list views
role_ids_stored = fields.Many2many(
    comodel_name="res.users.role",
    compute="_compute_role_ids_stored",
    store=True,
    groups="base.group_erp_manager",
)

and views/user.xml replaces base_user_role's user_role_ids column in view_res_users_tree_inherit with it (priority 99). The stated reason is that the OCA computed field did not render in the users list.

OCA/server-backend #428 ("[19.0][FIX] base_user_role: Cannot see User Roles", merged 2026-09-04, cc051ce6) is a fix for exactly that symptom: it renamed role_ids → user_role_ids, reworked the compute, and the OCA list view now shows user_role_ids with many2many_tags directly. So the workaround may be papering over a bug that no longer exists.

To check

1. On a 19.0 build with current OCA head, temporarily drop view_res_users_tree_inherit_spp_user_roles and confirm the Roles column renders (and updates when a role line is disabled / expires) from OCA's own user_role_ids.
2. Confirm nothing else reads role_ids_stored. git grep on 19.0 finds it only in spp_user_roles/models/user.py and spp_user_roles/views/user.xml; check customer overlays too.
3. Note the OCA field is a computed One2many, not stored, so it cannot be searched/grouped on in the list. If we rely on search-by-role anywhere (filters, exports), the stored field still earns its place and this issue should be closed as "keep".

If it is redundant

• Remove the field, its compute, and the list-view override; keep the form inherit and the hide-role-column view.
• Migration to drop the res_users_res_users_role_rel-style m2m table (check the actual relation name) so upgraded databases do not keep an orphan table.
• Bump spp_user_roles (currently 19.0.2.0.2), add HISTORY entry.

Small, self-contained PR; not urgent. Depends on nothing.