bug: Clear buttons have different font-size on Mac and iOS

### Prerequisites

- [x] I have read the [Contributing Guidelines](https://github.com/ionic-team/ionic-framework/blob/main/docs/CONTRIBUTING.md#creating-an-issue).
- [x] I agree to follow the [Code of Conduct](https://ionicframework.com/code-of-conduct).
- [x] I have searched for [existing issues](https://github.com/ionic-team/ionic-framework/issues) that already report this problem, without success.

### Ionic Framework Version

v8.x

### Current Behavior

The **clear** and **solid / outline** buttons have differenty font-sizes on iOS and macOS.

**Clear button:**

>

**Outline button:**

>

### Expected Behavior

All buttons should have the same font-size

### Steps to Reproduce

1. Use a Mac or iOS device
2. Go to https://ionicframework.com/docs/api/button#fill
3. Open the developer console
4. Compare the font-style of the clear and solid / outline button

### Code Reproduction URL

https://ionicframework.com/docs/api/button#fill

### Ionic Info

No need for that

### Additional Information

_No response_

Start with the button examples at https://ionicframework.com/docs/api/button#fill and compare the clear, solid, and outline button styles on macOS and iOS. Trace those examples to the button styling entry point, then verify that all three variants use the same font-size across both platforms.

Written by the indexing model from the issue text.