[BUG] [typescript-fetch] Undefined members imported in models when withoutRuntimeChecks is on

Created by: umbopepato

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?
• What's the actual output vs expected output?
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Description

When the withoutRuntimeChecks option is on, the missing members exists and mapValues are imported from runtime.ts in models, causing a TS compilation error:

Those two exports are in fact not defined when the mentioned option is on:

https://github.com/OpenAPITools/openapi-generator/blob/b9a6be0cba2fc21913bafba60a69e7815a336b98/modules/openapi-generator/src/main/resources/typescript-fetch/runtime.mustache#L278-L283

https://github.com/OpenAPITools/openapi-generator/blob/b9a6be0cba2fc21913bafba60a69e7815a336b98/modules/openapi-generator/src/main/resources/typescript-fetch/runtime.mustache#L312-L319

openapi-generator version

6.2.1

OpenAPI declaration file content or url

Generation Details

$ openapi-generator [...] --additional-properties=withoutRuntimeChecks
                                                  ^^^^^^^^^^^^^^^^^^^^

Steps to reproduce

• Generate a typescript-fetch client with the withoutRuntimeChecks option on.
• Run TS compilation on generated files.

Related issues/PRs

Suggest a fix

PR #14024 fixes this