feat: tab-bar fades in on scroll on iOS

### Prerequisites

- [X] I have read the [Contributing Guidelines](https://github.com/ionic-team/ionic-framework/blob/main/.github/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 include this feature request, without success.

### Describe the Feature Request

The tab-bar fades in on scroll on iOS similar to the footer and header, footer and header components have `collapse="fade"` option for this purpose.

### Describe the Use Case

It seems it was missed out when adding iOS 16 features to v6, by adding this feature tab-bar component, it behaves more like the latest iOS and it will increase the progress of the newest iOS features in v6.

### Describe Preferred Solution

_No response_

### Describe Alternatives

_No response_

### Related Code

_No response_

### Additional Information

_No response_

Start by locating the tab-bar component and reviewing how the header and footer implement the existing collapse="fade" behavior. Determine how scrolling is handled for iOS 16 features and define the expected fade-in and fade-out states for the tab bar. Done means the tab bar follows the iOS scrolling behavior and the relevant component tests or checks pass.

由索引模型根据 Issue 内容生成。