Support monitor arg for bmgr restore, and include detailed agent logs

Bug: 272551810
Test: adb shell bmgr backupnow com.android.wallpaperbackup --monitor; adb shell bmgr restore 1 com.android.wallpaperbackup (http://go/paste/5502576853254144)
Change-Id: Idc3e288f2548448d9a39f69096e33def783e3853