bug(form-field): Outlined form-field should have enough space to contain floating label

### 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

When using `outline` appearance for `mat-form-field`, the floating label overflows out of component itself. The `mat-form-field` component should have enough space on top to contain floating label. See below screenshot for reference:

### Reproduction

StackBlitz link: https://stackblitz.com/edit/rxp9hmcc?file=src%2Fexample%2Fform-field-appearance-example.html

### Expected Behavior

The `mat-form-field` component should have enough space (margin) on top to contain floating label.

### Actual Behavior

The `mat-form-field` component does not have enough space (margin) on top to contain floating label.

### Environment

- Angular: 20
- CDK/Material: 20
- Browser(s): Chrome
- Operating System (e.g. Windows, macOS, Ubuntu): macOS

Commencez par la reproduction StackBlitz liée et son exemple d’apparence de champ de formulaire, puis examinez la mise en page et les styles du mat-form-field outlined d’Angular Material impliqués dans le label flottant. Le travail est terminé lorsque le composant outlined fournit suffisamment d’espace en haut pour le label flottant sans débordement dans l’environnement signalé avec Angular 20, Chrome et macOS.

Rédigé par le modèle d'indexation à partir du texte de l'issue.