bug: migration script doesn't work for angular 19

### Prerequisites

- [X] I agree to follow the [Code of Conduct](https://ionicframework.com/code-of-conduct).
- [X] I have searched for [existing issues](https://github.com/ionic-team/ionic-angular-standalone-codemods) that already report this problem, without success.

### Codemod version

0.3.0

### Current Behavior

In Angular 19, components are now standalone by default, so the flag is not present which cause the script to not run and show the following message :

Cannot add import to component decorator. Component is not standalone.

### Expected Behavior

add misssing standalone ionic components in the imports array.

### Steps to Reproduce

1. Install angular 19
2. install ionic-angular-standalone-codemods 0.3.0
3. Run npx @ionic/angular-standalone-codemods

### Code Reproduction URL

_No response_

### Additional Information

_No response_

Start by reproducing the codemod failure with Angular 19 and inspect the standalone-component detection used by the migration script. Confirm the missing standalone Ionic components are added to the imports array without requiring the absent flag.

索引モデルが issue の本文から書いたものです。