TEST_MAPPING: remove the auto-features-postsubmit configuration

This test group has been moved to another test configuration,
v2/aaos-engprod/cts-cf-auto-md-stable_3, as part of the FrameworksMockingServicesTests
module.

Bug: 256932212
Test: git diff
Change-Id: I77f633711b64004aa9af4955243c412c0c138cb7
Signed-off-by: Lucas Henneman <henneman@google.com>