alternatives to change TestBed configurations without creating the test.ts files

### Which @angular/* package(s) are relevant/related to the feature request?

core

### Description

with Angular 15, now the `test.ts` file doesn't get generated by default, so it's not an easy task to change the `TestBed` configurations for example to enable `errorOnUnknownElements`
it will also be nice if we can change the pattern of the tests

### Proposed solution

to add the configurations inside the `angular.json` files in the options section of test

something like

```
"options": {
"polyfills": [
"zone.js",
"zone.js/testing"
],
"tsConfig": "tsconfig.spec.json",
"inlineStyleLanguage": "scss",
"assets": [
"src/favicon.ico",
"src/assets"
],
"styles": [
"src/styles.scss"
],
"scripts": [],
"errorOnUnknownElements": true, <---
"errorOnUnknownProperties": true, <---
"pattern": "\.custom-spec\.ts$" <---
}
```

### Alternatives considered

to be able to enable them globally from any script (to create a js file and add it to the scripts of the test) with something like

```
getTestBed().setoptions({
errorOnUnknownElements: true,
errorOnUnknownProperties: true,
pattern: /\.custom-spec\.ts$/
});
```

まず、angular.json のテストオプションがどのように処理され、test.ts のブートストラップがどのように生成または置き換えられるかを追跡します。要求された TestBed 設定とカスタムテストパターンを受け入れ条件として使用します。プロジェクトが test.ts ファイルを作成せずにそれらを設定できれば完了です。

索引モデルが issue の本文から書いたものです。