Component schematic adds redundant standalone flag and reverts to legacy `.spec.ts` when flag is removed

## Description

With Angular 19, components are standalone by default and do not require an explicit `standalone: true` flag. The `@ionic/angular-toolkit:component` schematic exhibits two inconsistent behaviors:

1. **With `"standalone": true` in `angular.json` schematics**
- The generated component and test scaffold are correct for standalone usage.
- **However**, the component decorator still includes `standalone: true` explicitly, which is redundant in Angular 19.

2. **Without the `standalone` option in schematics**
- The generated component decorator omits `standalone: true` (correct).
- The generated test `.spec.ts` falls back to the legacy NgModule-based pattern:
```ts
TestBed.configureTestingModule({
declarations: [TestComponent],
imports: [IonicModule.forRoot()]
}).compileComponents();
```
rather than the standalone pattern:
```ts
TestBed.configureTestingModule({
imports: [TestComponent],
}).compileComponents();
```

This inconsistency forces maintainers to either keep a redundant flag in their code or manually update specs.

---

## Current Behavior

- **With** `standalone: true` in schematics:
- Component decorator contains `standalone: true`.
- Test spec uses standalone-compatible setup.
- **Without** `standalone` in schematics:
- Component decorator is correct (no `standalone`).
- Test spec uses `declarations` and `IonicModule.forRoot()`, i.e., NgModule-based.

---

## Expected Behavior

- The schematic should **not** inject `standalone: true` in the component decorator (Angular 19 default).
- The `.spec.ts` should consistently use the standalone testing pattern, regardless of the schematics `standalone` setting:
```ts
TestBed.configureTestingModule({
imports: [TestComponent],
}).compileComponents();
```

---

## Reproduction Steps

1. Create a new Ionic + Angular 19 project:
```bash
ionic start myApp blank --type=angular
cd myApp
npm install @ionic/angular-toolkit@latest
```
2. **Case A:** Add to `angular.json`:
```jsonc
"schematics": {
"@ionic/angular-toolkit:component": {
"styleext": "scss",
"standalone": true
}
}
```
- Run `ionic generate component test`
- Observe redundant `standalone: true` in `test.component.ts`.
3. **Case B:** Remove the `standalone` option:
```jsonc
"schematics": {
"@ionic/angular-toolkit:component": {
"styleext": "scss"
}
}
```
- Run `ionic generate component test`
- Observe legacy NgModule-based test in `test.component.spec.ts`.

---

## Environment

- **@ionic/angular:** 8.5.5
- **@ionic/angular-toolkit:** 12.2.0
- **Angular CLI:** 19.2

---

Thank you for looking into this! Please let me know if you need further details.