[14.0][FIX][IMP] web_ir_actions_act_multi: uninstall issue

[sajadkk]

This commit fixes uninstallation issue of web_ir_actions_act_multi module. At the time of uninstallation, it removes several columns like name, binding_model_id, binding_type, binding_view_types... from ir_actions, ir_act_server, etc. This makes the database not usable anymore.

Fixes #2394

[sajadkk]

it doesn't break the intended functionality

[baguenth]

@matiasperalta1 Can you may also take a look? This was initially added by you. Maybe you can also remember why adding _table in the first place? In general I am confused why we need the .py-part at all.