ClientModeImpl: Add handleSupplicantStateChange() in RoamingState

Without this patch, DUT cannot automatically connect with a network
after disconnecting in RoamingState because isSupplicantTransientState()
returns true forever.

Bug: 161288559
Test: atest com.android.server.wifi.ClientModeImplTest
Change-Id: Id56212067883304430966acf391dcdcd6a7875fc
2 files changed