Don't allow to create a window in an unassigned display.

In MUMD (Multiple Users on Multiple Displays) environment, activities
can be launched in the displays to which the user is assigned. But
it is blocked to launch activities to unassigned displays.
Similar to the activity, this patch prevent system alert windows,
toast window and dialog from being shown in the unassigned displays.

Bug: 312321592
Test: atest WindowManagerServiceTests

(cherry picked from https://partner-android-review.googlesource.com/q/commit:e9da1c235fe75621693fa05aa1cdbb3638feac02

)
Change-Id: Ia88006b2ffee5d342535b26f2ad3e698bd6604c1
Signed-off-by: Dohyun Lee <dohyun.lee@lge.com>