Fix sysui's security issue of cross-user copy/paste

Background:
The applications with the granted INTERNAL_SYSTEM_WINDOW and
INTERACT_ACROSS_USERS_FULL means that it could show the same
window for all of users. i.e. to use user 0 presents all of
UI things to all of users.

INTERNAL_SYSTEM_WINDOW usually comes with INTERACT_ACROSS_USERS_FULL
because it will serve all of users to know the information that
comes from framework and system server.

Solution:
Because SystemUI never restarts after the user changing,
ClipboardService can't tell if the callingUid has the the same userId
with the current user or not.  The solution is to use the permission
check. Especially, INTERACT_ACROSS_USERS_FULL and
INTERNAL_SYSTEM_WINDOW. To check INTERACT_ACROSS_USERS_FULL by using
ActivityManagerInternal.handleIncomingUser.

Caution:
The application with INTERNAL_SYSTEM_WINDOW usually use user 0
to show the window. But, the current user is user 10, WindowManager
know the focus windows is belong to user 0 rather user 10. That's
why user 10 can't copy the the text from systemui directly reply to
the other applications.

Readability:
ClipboardService use callingUid everywhere but actaully it is not
appropriated to fix this kind of bug. This patch refactor the naming
to produce two name. i.e. intendingUid and intentdingUserId that are
validated by ActivityManagerInternal.handleIncomingUser.

Test: manual test
Test: atest android.widget.cts.TextViewTest
Test: atest CtsTextTestCases
Test: atest CtsContentTestCases

Bug: 123232892
Bug: 117768051
Change-Id: Ie3daecd1e8fc2f7fdf37baeb5979da9f2e0b3937