TestBed.overrideComponent doesn't work with AOT and webpack

### Command

test

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

TestBed.overrideComponent and TestBed.overrideModule don't seem to work with karma, webpack builder (builderMode: browser) and aot enabled. Changing any of these settings, so builderMode: application or disabling aot "fixes" the problem. The same issue was reported here https://github.com/angular/angular-cli/issues/30017 but i guess it was only fixed for esbuild? Is there any workaround for this? or can it be fixed for angular20?

### Minimal Reproduction

Create a simple valid component, turn on AOT for Karma, and make a test where you use TestBed.overrideComponent to reset metadata. You don't even need to specify an actual override in the second parameter to trigger the issue: TestBed.overrideComponent(YourComponent, {}) triggers the failure.

builderMode: browser needs to be set

### Exception or Error

```text
Error: App class doesn't have @Component decorator or is missing metadata.
at invalidTypeError (node_modules/@angular/core/fesm2022/testing.mjs:1661:12)
at forEach (node_modules/@angular/core/fesm2022/testing.mjs:1084:23)
at asyncGeneratorStep (node_modules/@babel/runtime/helpers/esm/asyncToGenerator.js:3:1)
at apply (node_modules/@babel/runtime/helpers/esm/asyncToGenerator.js:17:1)
at _ZoneDelegate.invoke (node_modules/zone.js/fesm2015/zone.js:398:28)
at ProxyZoneSpec.onInvoke (node_modules/zone.js/fesm2015/zone-testing.js:2132:39)
```

### Your Environment

```text
_ _ ____ _ ___
/ \ _ __ __ _ _ _| | __ _ _ __ / ___| | |_ _|
/ △ \ | '_ \ / _` | | | | |/ _` | '__| | | | | | |
/ ___ \| | | | (_| | |_| | | (_| | | | |___| |___ | |
/_/ \_\_| |_|\__, |\__,_|_|\__,_|_| \____|_____|___|
|___/

Angular CLI: 20.3.18
Node: 22.22.0
Package Manager: npm 10.9.4
OS: win32 x64

Angular: 20.3.17
... common, compiler, compiler-cli, core, forms
... platform-browser, router

Package Version
---------------------------------------
@angular-devkit/architect 0.2003.18
@angular-devkit/build-angular 20.3.16
@angular-devkit/core 20.3.18
@angular-devkit/schematics 20.3.18
@angular/build 20.3.18
@angular/cli 20.3.18
@schematics/angular 20.3.18
rxjs 7.8.2
typescript 5.9.3
zone.js 0.15.1
```

### Anything else relevant?

_No response_

Inizia con la riproduzione minima: un test del componente che utilizzi TestBed.overrideComponent o TestBed.overrideModule con Karma, il webpack builder in browser mode e AOT abilitato. Confronta l’errore con application builder mode o con AOT disabilitato, quindi verifica che il test di override venga eseguito senza l’errore relativo ai metadati @Component mancanti nella configurazione interessata.

Scritto dal modello di indicizzazione a partire dal testo della issue.