bug(mat-hint & mat-error): Font scaling breaks layout of mat-hint and validation messages

### 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 font scaling is increased (e.g. via browser/system settings), `mat-hint` and validation messages (`mat-error`) for input fields overflow into the next content block, breaking layout and readability.

### Reproduction

StackBlitz link: https://stackblitz.com/edit/vjrf1ddz?file=src%2Fexample%2Fform-field-appearance-example.html
Steps to reproduce:
1. Increase font size in browser settings to very big.
2. Observe how hint and error messages overlap or push into adjacent content.

### Expected Behavior

- Hint and error messages should remain visually associated with their input fields.
- Layout should adapt to font scaling without breaking structure.

### Actual Behavior

- Text overflows or overlaps with unrelated content.
- Layout becomes confusing or unreadable.

### Environment

- Angular: 20.0.3
- CDK/Material: 20.0.3
- Browser(s): Microsoft Edge, Google Chrome
- Operating System (e.g. Windows, macOS, Ubuntu): Windows

从 src/example/form-field-appearance-example.html 中的 StackBlitz reproduction 开始，并在 Chrome 或 Edge 中使用非常大的浏览器字体大小重现该问题。跟踪输入字段周围 mat-hint 和 mat-error 的布局；完成的标准是它们的文本仍与字段保持关联，不会覆盖相邻内容或变得难以阅读。

由索引模型根据 Issue 内容生成。