Fix fail of AutomaticStorageManagerSwitchBarControllerTest

initializingSwitchDoesNotTriggerView initializes mController
with a mSwitchBar which has already addOnSwitchChangeListener,
it will trigger onSwitchChangedon (and a dialog breaks the test)
of a mController initialized at setUp().

This change initializes a new mSwitchBar for the test.

Bug: 214907475
Test: make RunSettingsRoboTests ROBOTEST_FILTER=AutomaticStorageManagerSwitchBarControllerTest
Change-Id: Iefe56387c56ca6b1c2520c050467d130182ccfdc