Fix ImeiInfoPreferenceControllerTest

For test case updatePreference_simSlotWithoutSim_notSetEnabled,
mSecondSimPreference is a mock, instead of check the default value of
isEnabled(), verify it's setEnabled() not called.

Fix: 279880808
Test: RobolectricTest
Change-Id: I72064820754e053def46bdbf10317189c7ac608f