SoftApManager: Move SoftApManager to WifiStateMachine thread

This was changed to Wifiservice handler thread in ag/1202581. Reverting
back to WifiStateMachine's thread because I think the previous change was
unintentional. SoftApManager should run in the same thread as
WifiStateMachine.

Bug: 70146335
Test: Unit tests.
Test: SoftAp turns on/off.
Test: Will send for regression tests.
Change-Id: Ic2ff28cd6f726b77353f9abacbb451f95fc763ac
1 file changed