Fix ToggleFeaturePreferenceFragmentTest#setupFragment_getExpectedPreferenceScreenResId

**Root cause**
Robolectric doesn't like to launch a spy'ed fragment. You will get an
error like java.lang.IllegalStateException: Can't access ViewModels from detached fragment

Since the test itself doesn't require launch a fragment, I removed the
setup part and renamed the test.

Bug: 279082331
Test: atest ToggleFeaturePreferenceFragmentTest
Change-Id: Iafc431fd8c9cf7812ea99164e5e85683f3e0c121