Investigate: Another Common Type for Availability Zone

[tombuildsstuff]

SQL @ 2023-02-01-preview now contains:

type AvailabilityZoneType string

const (
	AvailabilityZoneTypeNoPreference AvailabilityZoneType = "NoPreference"
	AvailabilityZoneTypeOne          AvailabilityZoneType = "1"
	AvailabilityZoneTypeThree        AvailabilityZoneType = "3"
	AvailabilityZoneTypeTwo          AvailabilityZoneType = "2"
)

func PossibleValuesForAvailabilityZoneType() []string {
	return []string{
		string(AvailabilityZoneTypeNoPreference),
		string(AvailabilityZoneTypeOne),
		string(AvailabilityZoneTypeThree),
		string(AvailabilityZoneTypeTwo),
	}
}

func (s *AvailabilityZoneType) UnmarshalJSON(bytes []byte) error {
	var decoded string
	if err := json.Unmarshal(bytes, &decoded); err != nil {
		return fmt.Errorf("unmarshaling: %+v", err)
	}
	out, err := parseAvailabilityZoneType(decoded)
	if err != nil {
		return fmt.Errorf("parsing %q: %+v", decoded, err)
	}
	*s = *out
	return nil
}

Which differs from other services - we need to investigate whether this needs to become a new Common Type (e.g. is centrally defined/used as a common swagger type) - and then create custom Expand and Flatten functions to normalise this on our side.

[tombuildsstuff]

Checking the Swagger repository, it looks like this is specific to SQL at present: https://github.com/pmahanandire/azure-rest-api-specs/blob/0a58e97bb58d5e878b628511a0b29111bd184e95/specification/sql/resource-manager/Microsoft.Sql/preview/2023-02-01-preview/Databases.json#L1404-L1417