Start sensor service in a seperate thread

StartSensorService is taking ~141.8ms on marlin to start
With this CL, StartSensor will be done in a seperate
thread so the SystemServer can continue booting

Bug: 33199244
Bug: 33623300
Test: on marlin
Change-Id: I9e486d61e85072d5cbe69b1671c8fbfeca9c2200
(cherry picked from commit f94016d9)