[FIX] web: fixed css of hidden input file: a hidden element could interfere with other elements
in the dom, leading to some fields not being accessible.
[FIX] ir_actions: server action: check the validity of write_expresison only if defined. Also check for the related model only if set in the onchange.
[FIX] ir_actions: server action: when creating or writing value on a record
through a server action, try to correctly set the value to write on a given
fields according to its type. For example many2one fields should receive an
int, not a unique containing the id of the new value.