Reverts 5d33701. Unconditionally injecting SSE(INVALID_TAG) on
non-AEAD updateAad matched the AOSP TA spec but diverged from
real-device behavior on mt6768, which returns silently. A
behavior-fingerprint detector on the Xiaomi probe flagged the
divergence and the Tamper score climbed from 4 to 14, with a
second detector raising key-tamper. Roll back to investigate a
device-conformant approach.