The new `defaultInput` breaks multiple generators

[jorgenosberg]

The new defaultInput structure with multiple levels of inheritance with allOf breaks in multiple generators.

The following generators are confirmed to break at the generation stage:

• spring (server)
• python (client)
• java (client)
• csharp (client)

The following generators break when compiling/building generated code:

• aspnetcore (server)
• kotlin-spring (server)
• spring (server), since there's nothing to build
• python (client), since there's nothing to build
• kotlin (client)
• java (client), since there's nothing to build
• csharp (client), since there's nothing to build
• typescript-axios (client)

[jorgenosberg]

If not clear by looking at defaultInput, this problem extends to anything with more than 1 level of allOf inheritance. E.g. errors from the typescript-axios generator include:

api.ts(133,18): error TS2430: Interface 'AncillaryInput' incorrectly extends interface 'LegInput'.
  Types of property ''type'' are incompatible.
    Type '"ancillary"' is not assignable to type '"leg"'.
api.ts(183,18): error TS2430: Interface 'AssetInput' incorrectly extends interface 'LegInput'.
  Types of property ''type'' are incompatible.
    Type '"asset"' is not assignable to type '"leg"'.
api.ts(534,18): error TS2430: Interface 'ExtendExpiryTimeInput' incorrectly extends interface 'PackageInput'.
  Types of property ''type'' are incompatible.
    Type '"extend_expiry_time"' is not assignable to type '"package"'.
api.ts(811,18): error TS2430: Interface 'LegInput' incorrectly extends interface 'PackageInput'.
  Types of property ''type'' are incompatible.
    Type '"leg"' is not assignable to type '"package"'.
api.ts(1397,18): error TS2430: Interface 'PurchasePackageInput' incorrectly extends interface 'SearchOfferInput'.
  Types of property ''type'' are incompatible.
    Type '"purchase_package"' is not assignable to type '"search_offer"'.
api.ts(1428,18): error TS2430: Interface 'RedressInput' incorrectly extends interface 'PackageInput'.
  Types of property ''type'' are incompatible.
    Type '"redress"' is not assignable to type '"package"'.