bug(MatButton): FAB with disabled state using alpha on background collisions

### 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

Because the disabled state background color is defined with alpha, FAB collide with page contents when disabled. There's no guideline anywhere stating that FAB should never get disabled, and a disabled FAB is even part of the documentation.

FAB stands for Floating Action Button according to https://m3.material.io/components/floating-action-button/overview so it should be assumed most uses will be with absolute or fixed positioning.

### Reproduction

StackBlitz link: https://stackblitz.com/edit/4rnhsm?file=src%2Findex.html,src%2Fexample%2Fbutton-overview-example.html,src%2Fexample%2Fbutton-overview-example.css
Steps to reproduce:
1. Have a FAB button
2. Make it disabled

### Expected Behavior

The button doesn't get visually mixed with the page contents. One potential solution would be to make the disabled state not use alpha.

### Actual Behavior

Page contents as partially visible background on the button decrease its readability.

### Environment

- Angular: 17.0
- CDK/Material: 17.0
- Browser(s): any
- Operating System (e.g. Windows, macOS, Ubuntu): any

StackBlitz の再現から始め、特に src/index.html、src/example/button-overview-example.html、src/example/button-overview-example.css を確認し、無効化された FAB の背景の衝突を確認してください。再現から無効化された FAB の MatButton スタイルを追跡し、文書化されていない配置制限に依存せず、無効化された FAB のコンテンツがページのコンテンツ上でも読みやすい状態を維持していることを確認してください。

索引モデルが issue の本文から書いたものです。