getCaptivePortalServerUrl requires CONNECTIVITY_INTERNAL or
MAINLINE_NETWORK_STACK on Q, and NETWORK_SETTINGS or
MAINLINE_NETWORK_STACK on R+.
Use CONNECTIVITY_INTERNAL on Q instead of NETWORK_SETTINGS to test it.
Bug: 172626873
Test: atest CtsNetTestCasesLatestSdk:ConnectivityManagerTest
Change-Id: I03309de945b198ad9b40d51d799d2619bb3179ea