Revert "new System API for preferred network mode"

This reverts commit 8a8832fd810710fd8fbd7868be49abff270a1013.

Reason for revert: Causing failures on git_pi-dev-plus-aosp for docs and aosp_sailfish.

Change-Id: I1801188e66420a67244b3223e26334c4650d56be
Merged-In: Ic108c484905f80783982a22e8152609257d684b5
2 files changed