Support for Terms & Conditions notification

- Added API to add T&C URL in the CaptivePortalData class, and to
indicate if the source is from Passpoint.
- Added source indication for the Venue URL API.
- Allow the connectivity service to send a new T&C acceptance
notification.
- Updated the merge method to prefer the Capport data over the
network agent data, if the source is not authenticated (not from
Passpoint).
- Propagate the Venue Friendly name to the captive portal activity
to be used instead of SSID, when available.

Bug: 162785447
Test: End-to-end test
Test: atest ConnectivityServiceTest
Test: atest CtsNetTestCasesLatestSdk:CaptivePortalDataTest
Test: atest NetworkNotificationManagerTest
Change-Id: I4e77c3b6c01941b03c46ad32da70c77e0fecac64