Issue number: Resolves#28514
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issue. -->
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## What is the current behavior?
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When using the `@ionic/angular` schematic in an Angular 17 project (`ng
add @ionic/angular`), developers will receive an error preventing the
schematic from running.
Additionally, the previous implementations of the schematic are out of
sync with the current state of the Ionic starters:
- `variables.css` is empty and missing Ionic's defaults
- `ionic.config.json` is not created
- Schematic does not have support for module vs. standalone projects.
## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->
- `ng add @ionic/angular` works with Angular 17 projects
- `ng add @ionic/angular` has fallback behavior for Angular 16 projects
using `AppModule`
- Schematics now includes the proper `variables.css` from Ionic starters
- Ionicons assets will no longer be copied when being added to a
standalone project
- Refactors a majority of the implementation to use the utilities that
come directly from `@angular-devkit/schematics` and
`@schematics/angular`.
- Sets the `@ionic/angular-toolkit` CLI configuration and schematics
configuration in the `angular.json`
- Creates missing `ionic.config.json`
## Does this introduce a breaking change?
- [ ] Yes
- [x] No
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and migration path for existing applications below. -->
## Other information
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screenshots of how the component looks before and after the change. -->
Dev-build: `7.5.5-dev.11700239837.1925bbdb`
To test this PR:
1. Install Angular CLI v17 - `npm install -g @angular/cli@17`
2. Create a new project - `ng new angular-17`
3. Use the dev-build: - `ng add
@ionic/angular@7.5.5-dev.11700239837.1925bbdb`
4. Confirm the prompts
5. Validate that `provideIonicAngular({})` is added to the
`app.config.ts`
6. Validate that `ionic.config.json` was created
7. Validate that `angular.json` was updated with the
`@ionic/angular-devkit` configurations
Now verify legacy behavior:
1. Install Angular CLI v16 - `npm install -g @angular/cli@16`
2. Create a new project - `ng new angular-16`
3. Use the dev-build - `ng add
@ionic/angular@7.5.5-dev.11700239837.1925bbdb`
4. Confirm the prompts
5. Validate that `IonicModule.forRoot({})` is added to the
`app.module.ts`
8. Validate the ionicons glob pattern is added to the `angular.json`
9. Validate the `ionic.config.json` was created
10. Validate the `angular.json` was updated with the
`@ionic/angular-devkit` configurations
