Fix temporary key deletion after device ID attestation

After device ID attestation has been performed, the key used for it
should be deleted. Calling directly into the keymaster HAL for this
is wrong as it removes the key from keymaster but still leaves the
actual key matter around and the alias visible to KeyStore.

The key should be deleted using the KeyStore's delete method.

Bug: 37522655
Test: GTS DeviceIdAttestationHostTest

Change-Id: If3da9913fb54b077d3471f82269341966b1687e4