A user reported that the sign-in reminder isn't show when their phone starts.

While looking into power management I found that many phones restrict which apps can receive the boot completed broadcast. As with other power management restrictions, there's sometimes an intent for opening the screen where this is managed:

https://stackoverflow.com/questions/48945300/how-to-open-window-of-autostart-application-for-all-devices/48945679#48945679

https://stackoverflow.com/questions/48166206/how-to-start-power-manager-of-all-android-manufactures-to-enable-background-and#

Related to #1260 (closed), #1292.