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?
• [Optional] Bounty to sponsor the fix (example)

Description

Abstract typescript generator makes sure the generated model names do not conflict with reserved words / builtin objects.
However, with typescript-angular, this check is performed before the model suffix is appended, thus returning a false positive and ending up with a bogus model name.

openapi-generator version

Latest master and latest stable

OpenAPI declaration file content or url

Example schema: https://gist.github.com/amakhrov/1185d166a5c9ea6fc72de709a7be3795
The important part is that the model is called Error which is a name of a built-in object in TS:

definitions:
  Error:
    ... model definition

Command line used for generation

java -jar ./openapi-generator/modules/openapi-generator-cli/target/openapi-generator-cli.jar generate \
    -i  https://gist.githubusercontent.com/amakhrov/1185d166a5c9ea6fc72de709a7be3795/raw/e619d67f1d4e126981cd2ce900d46adee891cd32/example-schema.yaml \
    -g typescript-angular \
    --config ./config.json \
    -o ./generated

// config.json
{"modelSuffix":"Model"}
```

##### Steps to reproduce

- Run the command above.
- Check generated `models/error.ts` file

Expected model name: `ErrorModel`
Actually generated model name: `ModelErrorModel`

##### Suggest a fix

TODO: add link to PR