[SB][Wifi] Update content description for instant tether in QS tile.

Bug: 265342892
Test:  `adb shell am broadcast -a com.android.systemui.demo -e command
    network -e wifi show -e hotspot {tablet/laptop/watch/etc}` -> verify
    status bar wifi icon content description is the same as before.
    Verify Internet QS Tile content description contains "Connected to
    your device".
Test: atest InternetTileViewModelTest WifiViewModelTest
Change-Id: I6f225cf613b93dbebe5faaf955519ae394c10d69