[IMP] web: close dialogs when navigating to another action.

This commit fixes a problem of usability. By the past if several dialogs were opened
(e.g. after having clicked on several one2manys) and a user would click on a many2one in a dialog,
a new view was charged but the dialog was kept open so that the change was unnoticed.
This behavior has been changed. Now all dialogs are automatically closed in such a situation.