bug(mat-button-toggle): mat-button-toggle is 2px too tall

### 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

A `mat-button-toggle` is 2px taller than a `mat-stroked-button` despite both `--mat-standard-button-toggle-height` and `--mdc-outlined-button-container-height` both defaulting to 40px.

(this screenshot is at 2x zoom; each grid square is 2px)

### Reproduction

StackBlitz link: https://stackblitz.com/edit/components-issue-starter-bqkpddq3?file=src%2Fmain.ts

### Expected Behavior

`mat-stroked-button` and `mat-button-toggle` have the same height

### Actual Behavior

`mat-button-toggle` is 2px taller than `mat-stroked-button`

### Environment

```
> ng version

_ _ ____ _ ___
/ \ _ __ __ _ _ _| | __ _ _ __ / ___| | |_ _|
/ △ \ | '_ \ / _` | | | | |/ _` | '__| | | | | | |
/ ___ \| | | | (_| | |_| | | (_| | | | |___| |___ | |
/_/ \_\_| |_|\__, |\__,_|_|\__,_|_| \____|_____|___|
|___/

Angular CLI: 18.2.8
Node: 18.20.3
Package Manager: npm 10.2.3
OS: linux x64

Angular: 18.2.8
... animations, cdk, cli, common, compiler, compiler-cli, core
... forms, material, platform-browser, router

Package Version
---------------------------------------------------------
@angular-devkit/architect 0.1802.9
@angular-devkit/build-angular 18.2.9
@angular-devkit/core 18.2.9
@angular-devkit/schematics 18.2.8
@schematics/angular 18.2.8
rxjs 7.8.1
typescript 5.5.4
zone.js 0.14.10
```

src/main.ts の StackBlitz 再現から始め、報告された Angular バージョンで mat-button-toggle と mat-stroked-button を比較します。2 つのコンポーネントのレンダリング後の高さを追跡し、再現で示されているように両方のコントロールの高さが同じであることを確認して修正を検証します。

索引モデルが issue の本文から書いたものです。