[BUG][JAVA][Typescript] Nested additionalProperties not working

[gbertoncelli]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?

Description

When trying to describe a schema with nested additionalProperties the generator generate a type where the nested element is an object and not the nested additionalProperties type.

openapi-generator version

stable 4.2.3

OpenAPI declaration file content or url

https://gist.github.com/HighSoftWare96/e55d9bbeac3621e241eb8ba4b11fbcd3
Actual output - This example generates a type like this:

servicesStatus?: { [key: string]: { [key: string]: object; }; };

but the expected output should be:

servicesStatus?: { [key: string]: { [key: string]: { available: boolean }; }; };

Command line used for generation

openapi-generator generate -i oas3.json -o sdk -g typescript-angular

Steps to reproduce

• Create file oas3.json with the specified gist example
• Generate the SDK with the command above