Make device owner user command foreground

- Without this change there will be a 10 second delay before device owenr can receive the broadcast. Device owner is most likely in background when receiving the broadcast.
- The role of device owner is to manage user life cycle, e.g. create, remove, swithc, start, stop, it needs timely information to react quickly to provie smooth user experience. If every action requires a long time it will be a very bad user experience
- e.g. previous user finished, takes 10s for DO to realize user is logout, takes another 10s to realize user is created, 10s for new user is started etc. before DO can do the next action e.g. switch user, is a very sluggish user experience

Bug: 72305621
Test: With TestDPC, command now arrive faster
Change-Id: I8b0438efe75fbe2f029d7a3a111bf8f5035ce1a8