consider reducing the delay before the update prompt is displayed (ESR60)

After a browser update has been downloaded, users need to restart their browser to apply it. By default, a small badge is overlaid on the hamburger menu toolbar item to indicate that users should look in that menu for more info (where they will find a "Restart to update Tor Browser" menu item). In Tor Browser we have reduced the delay before the badge is displayed to zero.

The badge is kind of subtle though, so after some period of time the doorhanger prompt that is being discussed in #26048 (moved) is displayed. The delay before the doorhanger is displayed is currently: Firefox 60 release channel: 8 days Tor Browser: 2 days Kathy and Mark think we should reduce it further, maybe as short as on hour or two. The tradeoff is that the doorhanger is "in your face" and will somewhat interrupt people's work (although they can continue to use the browser with it open, and they can dismiss it without applying the update).