Handle radio unavailable state properly

In case of connecting state, setup data call might be ignored because
data HAL service gets dead so that data network gets stuck in connecting
state for long time.

Fixed by handling radio unavailable event in default state if the data
network is on WWAN. Also added special handling if the data network is
in handover state.

Bug: 387056127
Test: atest DataNetworkTest
Test: Basic telephony functionality tests
Flag: EXEMPT bug fix

Change-Id: I0a18d82ea76fe7540888b4f4c14948b804c81d0d