[BUG][typescript-angular] All properties generated with "?:" even when they are not optional

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?

Description

All properties generated by the openapi-generator are defined with ?: e.g.

/**
* Gets or sets the angle of reflection.
*/
angle?: number;

expected:

/**
* Gets or sets the angle of reflection.
*/
angle: number;

openapi-generator version

4.3.1

OpenAPI declaration file content or url

https://gist.github.com/Dunkhan/604694e5ae47c1162f784f1d3f3a78b9

Generation Details

npx openapi-generator generate -i D:\Work\testApi.json -g typescript-angular -c ./generate.api.options.json -o dist/api

generate options:

{  
   "npmName": "my-api",  
   "ngVersion": "9.1.0",
   "fileNaming": "kebab-case",
   "apiModulePrefix": "myPrefix"
}

Steps to reproduce

Run the command
Look in the file
\dist\api\model\effect-angle-values.ts

Related issues/PRs

none found

Suggest a fix

I am fully aware I might be doing something wrong, missing a flag, or reporting an intended behaviour. Please help me out if this is the case by explaining how I can get the generator to generate without the ?

I tried the flag nullSafeAdditionalProps but I found that this simply added "| null" to all nullable properties. This is good and I intend to keep using it but it does not solve the problem.

The reason this is an issue is that it I wish to use strict type checking and the properties being potentially undefined means that I have to fill all my code with undefined checks. These properties should never be undefined.

Reproduce the report with the shown openapi-generator command and inspect dist/api/model/effect-angle-values.ts, using the linked OpenAPI declaration as input. Trace the typescript-angular model generation entry point and its handling of required properties; done means generated required fields no longer use ?: while nullable behavior remains distinct.