Add tests for external storage related permissions for wallpaper apis

Test: atest CtsScopedStorageHostTest
Bug: 158316513
Merged-In: Idc2b8b41392a537e5c6e65f1cd95bc8dcac47068
Change-Id: Idc2b8b41392a537e5c6e65f1cd95bc8dcac47068
(cherry picked from commit 752fd18a10ddaee1959002d5bc7d8b3a79ffbded)
2 files changed