"CharSequence is more correct" than String.
Change method to take in CharSequence parameter and modify callers/tests.
Bug: b/74960034
Test: RunSettingsRoboTests:DataUsageSummaryPreferenceTest and RunSettingsRoboTests:DataUsageSummaryPreferenceControllerTest
Change-Id: Ic83bde57bafff8416c0bd86b1ff2beb44ea12d0e