fix: fixes s3 decode compiler errors

[kneekey23]

Description of changes

This PR fixes S3 compiler errors with decoding non optional associated values on enums. This additionally changes our decoding of enums with associated values from needing return statemetns everywhere to one switch statement based on the key in the container.

init(from decoder: Decoder) throws {
    let containerValues = try decoder.container(keyedBy: CodingKeys.self)
    let key = containerValues.allKeys.first
    
    switch key {
    case .empty:
        self = .empty
    case .domain:
        let domain = try container.decode(
            String.self,
            forKey: .editing
        )
        self = .domain(domain)
    case .port:
        let port = try container.decode(
            Int.self,
            forKey: .port
        )
        self = .port(port)
    default:
        self = .sdkUnknown("")
    }
}

Scope

• [ x] Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[wooj2]

Chatted offline - approving assuming that changes are made and unit tests do not need to be updated.

Thanks so much for handling this!