Secretkeeper: Use byte[64] as SecretId

SecretId is a parameter in deleteIds() method, which will be invoked by
host (Android). Restrict the size to 64 bytes to avoid unnecessarily
large bytes making it to HAL & TA.

Test: atest VtsSecretkeeperTargetTest
Bug: 317374882
Change-Id: Ieb34fee4efd11636bee133fe9132c1d739d08a1c
3 files changed