[TeseCase] unify the getResourcesString

Bug: 173099559
Test: atest PreferredNetworkModePreferenceControllerTest  (PASS)
atest OpenNetworkSelectPagePreferenceControllerTest (PASS)
atest MobilePlanPreferenceControllerTest            (PASS)
atest MobileDataPreferenceControllerTest            (PASS)
atest Enhanced4gLteSliceHelperTest                  (PASS)
atest AutoSelectPreferenceControllerTest            (PASS)

Change-Id: I9a2e3d69cbd933a1282d51b7d8869e6a1ec4cb14
8 files changed