[Flags][SB] Remove NEW_STATUS_BAR_WIFI flags.

There's likely some additional cleanup needed in StatusBarIconController
& associated classes once the mobile flags are also removed.

Fixes: 256614210
Fixes: 256613548
Test: smoke test of the wifi icon on phone, foldable, and tablet
Test: smoke test of wifi demo mode
Test: smoke test of Internet tile in QS
Test: atest StatusBarIconControllerTest NetworkControllerWifiTest
Change-Id: Ib20a3d664963ed289c27b8b6a432e554aad614d0