CaptivePortalData: use CharSequence in VenueFriendlyName API

Following up on feedback from API council, change the String type
to CharSequence in the get and set Venue friendly name API.

Bug: 179163405
Test: atest ConnectivityServiceTest CtsNetTestCasesLatestSdk:CaptivePortalDataTest
Test: atest NetworkNotificationManagerTest NetworkMonitorTest
Change-Id: I122f10af80970727054db8a7691241412636d99c
1 file changed