[FIX] board: traceback when removing calendar from dashboard
[FIX] board: traceback when removing calendar from dashboard

The dashboard instantiates an action manager for each view it contains.
When removing a view from the dashboard, the $el of its action manager
is simply removed from the DOM, unbinding all DOM event handlers
attached on it and its children, but the action manager isn't destroyed.
It means that Odoo event handlers (like core.bus.on(...)) aren't unbound.

This causes a traceback when removing a calendar view from the dashboard,
because such an Odoo handler is defined, and tries to access some
autocomplete stuff that doesn't exist anymore since the element has been
removed.

This commit ensures to destroy the action_manager.

Closes #13858

laslabs/odoo,laslabs/odoo,storm-computers/odoo,ygol/odoo,storm-computers/odoo,dfang/odoo,dfang/odoo,bplancher/odoo,ygol/odoo,laslabs/odoo,ygol/odoo,Elico-Corp/odoo_OCB,ygol/odoo,storm-computers/odoo,microcom/odoo,Elico-Corp/odoo_OCB,hip-odoo/odoo,hip-odoo/odoo,laslabs/odoo,dfang/odoo,bplancher/odoo,dfang/odoo,bplancher/odoo,dfang/odoo,hip-odoo/odoo,hip-odoo/odoo,Elico-Corp/odoo_OCB,bplancher/odoo,microcom/odoo,Elico-Corp/odoo_OCB,storm-computers/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo,microcom/odoo,Elico-Corp/odoo_OCB,microcom/odoo,hip-odoo/odoo,microcom/odoo,microcom/odoo,dfang/odoo,ygol/odoo,storm-computers/odoo,Elico-Corp/odoo_OCB,laslabs/odoo,bplancher/odoo,laslabs/odoo,storm-computers/odoo,bplancher/odoo