additionalProps type evalulation seems to have issues

[PeterMK85]

Describe the bug
With --export-types options the following declarations:

    Order:
      type: object
      additionalProperties:
          type: string

!Note: no properties defined

Will evaluate to:

type Order = {}

I think it should be:
Easy fix:

type Order = {[key: string]: string}

Or

type Order = Record<string, string>

As a workaround, I tried the following:

    Order:
      type: object
      properties: {}
      additionalProperties:
          type: string

Which yields to:

type Order = Partial<{} & {[key: string]: string}>

Minimal reproduction
Online example
(Modified the Order)

Expected behavior
I have a local patch to make it work I will open a PR today.

Additional context
Rootcause