Fix isSetWallpaperAllowed secondary user

isSetWallpaperAllowed calls hasUserRestriction
which has a permission check that was violated
because isSetWallpaperAllowed was calling from
the wrong user (the system rather than the
original caller).

Bug: 143958690
Test: Go to seconary user and try to change wallpaper
Change-Id: I42f8ed17fb76cb6f84d0c11266f163356656c0ac