Fixed choices are not generated properly in the typescript codegen

In https://github.com/digital-asset/daml/blob/f722cf13cda26fe1bb573004416ac944cf334789/language-support/ts/codegen/tests/ts/build-and-lint-test/src/__tests__/test.ts#L351 `buildAndLint.Main.Asset.Transfer` is `undefined`. It looks like somewhere we’re just not generating the code for the choice at all so the selector returns `undefined`