Remove attenuator-relevant codes since `WifiBaseTest` already handles this and it will set attenuation level to 0 if attenuator(s) are available. am: 6ff502c5e2

Original change: https://android-review.googlesource.com/c/platform/tools/test/connectivity/+/3238960

Change-Id: I1a63c2d9d25e5cd496252fbf6ff1cc8cd70c14df
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>