Revert "Settings(wifi): Allow mainline wifi stack to use network request dialog"

This reverts commit 6faf8649.

Reason for revert: Wifi services no longer plan to be a separate
APK/process for mainline. Will instead become a jar loaded from Apex.

Bug: 144722612
Change-Id: I1d29859866cec3af419fea4f0838d868d2fad8e5
Test: Device boots up & connects to wifi networks.