Unit test: Add reporter watermark configuration to angular.json

### Command

test

### Description

After taking advantage of all the new Vitest unit test features in 21.0.0, there is only one configuration item left in the vitest-base.config.ts:

```
export default defineConfig({
test: {
slowTestThreshold: 1000
}
});
```

This is required since the Vitest's [slowTestThreshold](https://vitest.dev/guide/cli.html#slowtestthreshold) default of 300 ms is not adequate for extended test cases.

Ideally this configuration should be available through the angular.json configuration unit-test options, since it would allow the complete removal of the vitest-base.config.ts file.

Maybe follow the nomenclature that you introduced with "coverageWatermarks" and call it "reporterWatermark".

### Describe the solution you'd like

_No response_

### Describe alternatives you've considered

_No response_

Comienza con las opciones de pruebas unitarias de angular.json y vitest-base.config.ts, y después ejecuta el comando de pruebas unitarias del repositorio para rastrear cómo llegan las opciones a Vitest. Confirma que la configuración deseada del umbral para las pruebas lentas se acepta a través de angular.json y que vitest-base.config.ts se puede eliminar sin perder la configuración.

Escrito por el modelo de indexación a partir del texto del issue.