[BUG][typescript-angular] Spec Server URL no longer used as default basePath

[kzander91]

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

After the refactoring made in #20681, the generated API controller services no longer define basePath on their own, but inherit it from the new BaseService.

Before:

export class DemoService {

    protected basePath = '/my/api/base/path';
    // ...
}

Template:

openapi-generator/modules/openapi-generator/src/main/resources/typescript-angular/api.service.mustache

Line 64 in a7240ee

protected basePath = '{{{basePath}}}';

After:

export class DemoServie extends BaseService {

   // ...
}

export class BaseService {
    protected basePath = '';
    // ...
}

Template (now hard-coded as ''):

openapi-generator/modules/openapi-generator/src/main/resources/typescript-angular/api.base.service.mustache

Line 6 in afc27ef

protected basePath = '';

openapi-generator version

7.12.0

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: demo
  version: "1.0"
servers:
  - url: /my/api/base/path
paths:
  /relative/path:
    get:
      tags:
        - demo
      responses:
        "200":
          description: OK

Generation Details

Steps to reproduce

Related issues/PRs

Suggest a fix

[daniel-sc]

I'll make a PR for this..