Skip testEcAttestation and testRsaAttestation if device has no lock screen

According to 8.1 CDD (9.11) a device must support key attestation when it
supports a secure lock screen, so skip these tests when the devices does not
support a secure lock screen.  A device must support a secure lock screen
when it reports the platform feature android.software.device_admin.  Here
we check for the lock screen the same way as the patch for testEncryption:
https://android-review.googlesource.com/c/platform/cts/+/944836



Change-Id: I62c571c31c3ee7cc013f91de2ee8d127b821799b
Signed-off-by: Tochau Hoang <tochau.hoang@panasonic.aero>