Handling `UNIMPLEMENTED` error code from deleteKey API in Keystore VTS
Tests.

Some of the older Keymaster implementations doesn't implement deleteKey
API. Updated Keystore VTS tests to ignore the UNIMPLEMENTED error code
from `IKeystoreSecurityLevel::deleteKey` API.

Bug: 383246972
Test: keystore2_client_tests
Change-Id: I97ae79b20202ce1ea949ebdda141ce9118b7352f
3 files changed