Allow 2-pane deep link to access unexported Activity

If an Activity is not exported, the Activity still can be
launched by components of the same application, applications
with the same user ID, or privileged system components.

Bug: 261678674
Bug: 250589026
Test: manual visual
      Launcher -> context menu -> Wallpaper & style
Change-Id: I662df6cb287361b135e2c596abe946ddeb03bda4
Merged-In: I662df6cb287361b135e2c596abe946ddeb03bda4