#6008 fix typescript fetch error "Object is possibly 'undefined'." for body requestParameters array mapping

Created by: ovirta

Adding null conditional operator to body requestParameters mapping. Fixes error: "Object is possibly 'undefined'."

Generating post api with a collection creates api interface with nullable collection but api method calls the nullable property without null conditional operator.

Example:

Original post api: public async Task<IActionResult> OnPost([FromBody] List<CreateSampleViewModel> model) { creates following code:

export interface VversionSamplePostRequest {
  createSampleViewModel?: Array<CreateSampleViewModel>
}

:

        body: requestParameters.createSampleViewModel.map(
          CreateSampleViewModelToJSON
        ),

-> Typescript complains about object being possibly undefined.

#6008

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