Update Monkey to lookup the current user so that it can execute against secondary users.

bug: 118503943
Test: cts-tradefed run cts-dev -a arm64-v8a -m CtsMonkeyTestCases -t com.android.cts.monkey.MonkeyTest#testIsMonkey
Change-Id: Id7d320fddfbf91d4451a4e141a91614ee9104dec