[Issuance V2] Pre-Auth Flow Complete

[symorton]

Problem: Complete the Pre-Authorization flow for Issuance V2.

Solution: Complete the Pre-Authorization flow for Issuance V2.

Validation: Works as expected.

Type of change:

• [X] Feature work
• [ ] Bug fix
• [ ] Documentation
• [ ] Engineering change
• [ ] Test
• [ ] Logging/Telemetry

Risk:

• [X] High – Errors could cause MAJOR regression of many scenarios. (Example: new large features or high level infrastructure changes)
• [ ] Medium – Errors could cause regression of 1 or more scenarios. (Example: somewhat complex bug fixes, small new features)
• [ ] Small – No issues are expected. (Example: Very small bug fixes, string changes, or configuration settings changes)

Work Item links: Please include here links for this work item, or deferred work, or related work. E.g. if the refactoring is too big to fit in this PR, or the localized strings need to be updated later, please link the TODO work items here.

Documentation Links: Please include here links to any related background documentation for this PR.

[mauesrog]

Overall okay but have a few questions/suggestions, and am still confused on the expiry time parameter as its unclear if this is "expiry in seconds" relative to initiated at, or since epoch time.

@logangirvin it is not relative to epoch. think of it as time to live in seconds. this is why we called it expires in and not expires at.