Reduce boilerplate in tests using direct component creation with bindings

[medbenmakhlouf]

Summary

This PR improves the test suite by leveraging the new testing APIs introduced in Angular 20.1+, allowing us to simplify component tests and remove unnecessary boilerplate.

Details

• Migrated existing tests to use the updated TestBed.createComponent options.
• Replaced extra "host" components with direct component testing, reducing redundancy and making tests easier to read.
• Introduced the use of bindings for input simulation:

const fixture = TestBed.createComponent(FaDuotoneIconComponent, {
  bindings: [
    inputBinding('icon', () => faDummy),
    inputBinding('secondaryOpacity', () => 0.9),
  ],
});

This makes input setup more explicit and avoids creating additional wrapper components.

Benefits

• Less boilerplate: Fewer wrapper/host components.
• Clearer tests: Inputs are defined directly where the component is created.
• Future-proof: Aligns test setup with Angular 20.1+ best practices.

[medbenmakhlouf]

@devoto13 thanks in advance for the review ;)

[devoto13]

Sorry for the late review!
LGTM