tetris: Use enable instead of start for neural networks & vtservice

* The MTK Neural Networks service is started via a property trigger.
  This HAL starts a lot earlier than other HALs since it is started
  with "start" instead of "enable", the difference between them being
  that "start" will immediately cause the service to try and start, while
  "enable" effectively removes the "disabled" attribute from the service
  (so in the case of a HAL, it will be started with all the other services
  in class hal instead of immediately).

* This initially didn't have any side effects until I noticed the Neural Networks
  service constantly crashing in offline charger mode. To fix this, simply
  convert the "start" command to an "enable" to ensure that this service is not
  only started at the right time (in class hal), but also only started when
  needed (and not in offline charger mode).

Change-Id: Iacf310fb2211117aaf028ad6bf0814a7d447cf53
Signed-off-by: bengris32 <bengris32@protonmail.ch>