The migrated 16.0 database still holds ``theme_ir_ui_view`` rows whose
``inherit_id`` points to ``ir.ui.view`` ids removed by the 17.0 asset
bundle rework (``web._assets_utils``, ``website.assets_editor``,
``website._assets_frontend_helpers`` replaced by the ``ir.asset`` model).
When ``website._theme_load`` runs during the registry load,
``ThemeView._convert_to_base_model`` accesses ``inherit.website_id`` on
the ghost record and raises ``MissingError``, aborting the whole
registry build.
Delete the ``ir_model_data`` + ``theme_ir_ui_view`` rows whose
``inherit_id`` targets a missing ``ir.ui.view``. Generic (covers any
theme), idempotent, scoped to ``theme_ir_ui_view`` only; no
``ir.ui.view`` copies exist for the affected templates.