Segmented control: should use `border` instead of `outline` for styling

[driskull]

Description

styles should use border instead of outline for styling

Proposed Advantages

Using a border is the proper way to define borders

Which Component

segmented-control, segmented-control-item

Relevant Info

Calcite package

• [X] @esri/calcite-components
• [ ] @esri/calcite-components-angular
• [ ] @esri/calcite-components-react
• [ ] @esri/calcite-design-tokens
• [ ] @esri/eslint-plugin-calcite-components