Refactor InternetIconInjector to SettingsLib

- Plan to share the InternetIconInjector class to System UI.

Bug: 192923176
Test: manual test
make RunSettingsLibRoboTests ROBOTEST_FILTER=WifiUtilsTest

Change-Id: Ieb7080ab6f6462abc3820b47c2a58cc2ea2a083e
2 files changed