Remove tint from network logging icon

Mirrors the change in commit 3250885c
("Visual refresh for QS") which removed tint from all ic_qs_xyz.xml
icons for quicksettings.

This one was missed because it was committed to nougat-mr2-dev and
only merged into the development branch afterwards.

Change-Id: I603c31aa82e9d52925fbe06d02a620036d93056e
Fix: 35620542
Test: adb shell am start 'android.app.action.SHOW_DEVICE_MONITORING_DIALOG' on a device with network logging enabled.