Fix test of triggerEmergencyNetworkScan

triggerEmergencyNetworkScan needs to be triggered after
setEmergencyMode.

Bug: 336706719
Test: atest VtsHalRadioTargetTest:PerInstance/RadioNetworkTest#triggerEmergencyNetworkScan/0_android_hardware_radio_network_IRadioNetwork_slot1 -- --abi arm64-v8a
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:df7692133547c051389a7eda5a134f8e82dfa163)
Merged-In: If32d594525bea3a4a4562e2b1070ef646744513f
Change-Id: If32d594525bea3a4a4562e2b1070ef646744513f