wifi: Call terminate in VTS teardown

When OEM register different hostapd instance without update the StopHostapd.
It will cause VTS clean fail because hostapd process name is the new
one.
Call terminate to request clean HAL state.

Bug: 161682236
Bug: 167636313
Test: atest -c VtsHalWifiHostapdV1_2TargetTest
Test: atest -c VtsHalWifiHostapdV1_1TargetTest
Test: atest -c VtsHalWifiHostapdV1_0TargetTest
Change-Id: If56e5b5351abd31865150bdf97d27674dbbc4257