Remove the feature of aggregation when performing manual network
selection.
Bug: 141287649
Test: Manual
make RunSettingsRoboTests -j ROBOTEST_FILTER=NetworkSelectSettingsTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=NetworkOperatorPreferenceTest
Change-Id: I813ad31f9d5cf310877442f5558e236671ab5d23