am: Don't take down activity process if target intent component is null.

  When no activity exists to handle a given action, the target component
  of the resolve will be null. Ignore this scenario for protected apps
  checks since there can be no component to protected.

TICKET: CYNGNOS-1755
Change-Id: I25d7d15d17c4b5ccd4fe9db6e6c9d57088feba2f