[flexiglass] Fix InternetAdapterTest with SceneContainerFlag

Converted to use `FlagsParameterization` for FLAG_QS_WIFI_CONFIG,
FLAG_QS_TILE_DETAILED_VIEW, and SceneContainerFlag.

Fixed an NPE by stubbing `mutate()` on mock Drawables
(mWifiDrawable, mGearIcon, mLockIcon) to return themselves.
This prevents ImageView from nullifying its internal drawable
when setColorFilter is called.

Bug: 416717352
Flag: com.android.systemui.scene_container
Test: com.android.systemui.qs.tiles.dialog.InternetAdapterTest
Change-Id: Ic280bc71939a81912c5830fd69b1f1c528461ed8