Fine tune UI layout files of WifiDppQrCodeScannerFragment &

WifiDppQrCodeGeneratorFragment

    1. Remove footer in landscape QR code scanner fragment
    2. Move header icon from activity layout file to header layout file
    3. Fine tune header layout file
    4. set icons for the 2 fragments

Bug: 118797380
Bug: 118794858
Test: atest WifiDppConfiguratorActivityTest
      atest WifiDppQrCodeScannerFragmentTest
      atest WifiDppQrCodeGeneratorFragmentTest
      atest RunSettingsRoboTests

Change-Id: I7e547d7c29dd947a890e902e61b8244fec399354