DPM: Propagate StrongBox-related exception

When the caller attempts to generate a key via DevicePolicyManager
(using DevicePolicyManager.generateKeyPair), and specifies that
StrongBox should be used, throw the right exception indicating
StrongBox unavailability - the same one that is thrown if the same
parameters were passed to the KeyStore's key generation method.

This is achieved by catching the StrongBoxUnavailableException in
KeyChain, returning an error code indicating this particular failure
to the DevicePolicyManagerService, which then propagates it by
throwing a service-specific exception with a value indicating
StrongBox unavailability.
The DevicePolicyManager then raises StrongBoxUnavailableException.

Prior to this change the exception propagated from KeyChain would be
a generic failure so the caller would simply get a null result.

Bug: 110882855
Bug: 111183576
Bug: 111322478
Test: atest CtsDevicePolicyManagerTestCases:com.android.cts.devicepolicy.MixedDeviceOwnerTest#testKeyManagement
Change-Id: I9abe3f449b48eb5a960fafbc15c59b9b4ce7a966