Before this rev. the lazy loading of views was correctly handled if there was
only one action in the action stack (which is usually the case when performing a
F5, the main use case of the view lazy loading).
Nevertheless, it might happen that the lazy-loading is used in top of other
actions (when performing a `doAction` with a form view for an action with
another view as first view, i.e. when leaving Studio while editing the form view).
The controller was `unshift` in the case (put in the first position of the
controller stack), which is not correct.
This causes the breadcrumb to be misordered and a traceback occured when trying
to access a breadcrumb element.
Co-authored-by: Aaron Bohy <aab@odoo.com>
