[FIX] web: do not keep additional context in stored action

Before this commit
The current action is stored in the session storage with its evaluated
context. This design is wrong because a context is by definition
contextual which means it has to be evaluated at the last possible
moment to ensure it reflects the most recent context.

After this commit
The current action is now stored in the session storage it its most
original state. This is sufficient as in any case actions go through
the doAction method which evaluates the context right before applying
the action logic.

Part-of: odoo/odoo#78555