human_motion_robot: remove obsolete owners BUG=None TEST=CQ Change-Id: I33ddb5cbd0655b054e7767c6502316348fb32dbe Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/human_motion_robot/+/7705819 Commit-Queue: Di Wu <[email protected]> Tested-by: Di Wu <[email protected]> Reviewed-by: Henry Barnor <[email protected]>