[Wi-Fi] Wi-Fi picker scrolls to top after a user clicked to connect

After a connect success callback, Wi-Fi picker scrolls to the connected
Wi-Fi network after it's added in.

Bug: 152576795
Test: make RunSettingsRoboTests ROBOTEST_FILTER=WifiSettings2
      manual
      Click a Wi-Fi network or it's context menu 'Connect' button
      to connect and see if  UI scroll to the top.
Change-Id: Ia96af86c9ed552324089f97db104975e28f6c1c7