Store more data for apps that are pending install

because when we reboot, we load data only once, as USER_ALL, and we may
have pending data for multiple users.

Bug: 334999659
Test: PreferencesHelperTest
Test: on source device, turn off a channel. restore to device,
reboot immediately, view notification settings
when app is installed. reboot again, view again

Change-Id: I11ff90ec652aafea5ea8a896331d60a0ea20d6b3