Make os_version optional for StrongBox

This change allows the os_version in the DeviceInfo map to be optional
for StrongBox implementations. It also adds the appropriate changes to
the VTS test to relax this requirement.

Bug: 215444522
Test: atest VtsHalRemotelyProvisionedComponentTargetTest
Change-Id: I1695b7c4e7a9bd884fa88c14f9c22bacd38cdbd3