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

Start with the linked StackBlitz reproduction and its form-field appearance example, then inspect the Angular Material outlined mat-form-field layout and styles involved in the floating label. Done means the outlined component provides enough top space for the floating label without overflow in the reported Angular 20, Chrome, and macOS setup.

Written by the indexing model from the issue text.