Add Handling for Relaxing Enum Validation at Deserialization Time

[mrafnadeem-apimatic]

Context

Our current behaviour applies strict validation to enum values at serialization and deserialization time and throws exceptions when any issue is found. Sometimes, however, the server will update its responses with new values. Server-side changes for different APIs may occur rapidly and as such it may be preferable to relax the validation at deserialization time.

Problem

We need to find a way to relax validation during deserialization for specific enums. We also need to maintain the validation during serialization.