[Enhancement] A11y improvements for Segmented Control

[henrikvoetmand]

• [x] I have written a good issue

Describe the enhancement

To make Segmented Control support proper announcing to screen readers we need to:

• [x] Announce total number of Segment tabs (1/1 -> 1/3) This is a known bug in Chrome with VoiceOver on macOS
• [x] Announce selected tab
• [x] Implement Tabs pattern from ARIA Authoring Practices Guide

Describe the solution you'd like

Have you considered any alternatives?

Are there any additional context?

Also filed a bug issue in the Ionic repo: ionic-team/ionic-framework#30022

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Checklist:

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