Remove CupertinoSegmentedControl from the widget catalog (#11787)

This removes the `CupertinoSegmentedControl` from the widget catalog.
Customers should instead use `CupertinoSlidingSegmentedControl`.
 
`CupertinoSegmentedControl` is the pre-iOS 13 - released in 2019 - look
for an iOS "segmented control".

Part of flutter/flutter#152910

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Author: loic-sharma

src/_data/catalog/widgets.yml

@@ -839,16 +839,6 @@
   link: https://api.flutter.dev/flutter/cupertino/CupertinoSearchTextField-class.html
   image:
     src: /assets/images/docs/widget-catalog/cupertino-search-field.png
-- name: CupertinoSegmentedControl
-  description: >-
-    An iOS-style segmented control. Used to select mutually exclusive options in
-    a horizontal list.
-  categories:
-    - 'Cupertino'
-  subcategories: []
-  link: https://api.flutter.dev/flutter/cupertino/CupertinoSegmentedControl-class.html
-  image:
-    src: /assets/images/docs/widget-catalog/cupertino-segmented-control.png
 - name: CupertinoSlider
   description: Used to select from a range of values.
   categories: