Reduce stepper track size from 0.25rem to 0.125rem

This further relaxes the component by taking away the attention from the track itself, allowing bubbles and text to be more easily readable at a glance without feeling overcrowded.

 The industry standard is 1px or 2px at max.

As a result, the stepper tracker has been reduced to down to `2px`  from `4px`

For reference:
- Tailwind UI practices `2px` width: https://tailwindcss.com/plus/ui-blocks/application-ui/navigation/progress-bars#component-4b1efed043d1ab5688c705f2e27524f3
- Material UI practices `1px` width: https://material.angular.dev/components/stepper/overview
- Preline UI practices `1px` width: https://preline.co/docs/stepper.html
- Flowbite UI practices `1px` width: https://flowbite.com/docs/components/stepper/
- ReUI practices `1px` width: https://reui.io/patterns/stepper

Author: pricop

scss/_stepper.scss

@@ -15,7 +15,7 @@ $stepper-tokens: defaults(
     --stepper-gap: 1rem,
     --stepper-font-size: var(--font-size-sm),
     --stepper-bg: var(--bg-2),
-    --stepper-track-size: .25rem,
+    --stepper-track-size: .125rem,
     --stepper-active-color: var(--primary-contrast),
     --stepper-active-bg: var(--primary-bg),
   ),