[Provider Model] Fix WiFi reconfiguration issue

- Need to set connectForCaller to be true when WiFi is reconfigured.

- Use a share function to create the internt to avoid different design.

Bug: 218793138
Test: manual test
make RunSettingsLibRoboTests ROBOTEST_FILTER=WifiUtilsTest
atest -c InternetAdapterTest \
         InternetDialogControllerTest

Change-Id: Ia57b4d91320f8e61e94d9ffd47e06648dfc24f3f