[cryptolib] Consider adding a keymgr API to read the maximum key version available.

### Description

Currently, it takes time to debug side load errors triggered by invalid KMAC inputs in the keymgr. One way to mitigate this issue is by adding an API to check the maximum key version allowed by the keymgr.

Start by inspecting the keymgr API and the validation path for KMAC inputs that produces side-load errors. Trace how the maximum permitted key version is represented and tested; done means the keymgr exposes that maximum and coverage verifies the reported value.

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