[Tabs] pressed state fix (#8990)

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### WHY are these changes introduced?

The pressed state of tabs turned the highlight color bright green. This
was a little jarring and not an optimal designer experience.

<!--
  Context about the problem that’s being addressed.
-->

### WHAT is this pull request doing?
This PR simply changes the tokens used for both the hover and active
state. Both are now using a bg token since the css attribute being
targeted is `background-color`. The active state is also now remaining
gray to fix the jarring experience where it turned bright green.


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### How to 🎩

🖥 [Local development
instructions](https://github.com/Shopify/polaris/blob/main/README.md#local-development)
🗒 [General tophatting
guidelines](https://github.com/Shopify/polaris/blob/main/documentation/Tophatting.md)
📄 [Changelog
guidelines](https://github.com/Shopify/polaris/blob/main/.github/CONTRIBUTING.md#changelog)

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<details>
<summary>Copy-paste this code in
<code>playground/Playground.tsx</code>:</summary>

```jsx
import React from 'react';
import {Page} from '../src';

export function Playground() {
  return (
    <Page title="Playground">
      {/* Add the code you want to test in here */}
    </Page>
  );
}
```

</details>

### 🎩 checklist

- [ ] Tested on
[mobile](https://github.com/Shopify/polaris/blob/main/documentation/Tophatting.md#cross-browser-testing)
- [ ] Tested on [multiple
browsers](https://help.shopify.com/en/manual/shopify-admin/supported-browsers)
- [ ] Tested for
[accessibility](https://github.com/Shopify/polaris/blob/main/documentation/Accessibility%20testing.md)
- [ ] Updated the component's `README.md` with documentation changes
- [ ] [Tophatted
documentation](https://github.com/Shopify/polaris/blob/main/documentation/Tophatting%20documentation.md)
changes in the style guide

---------

Co-authored-by: Alex Page <hi@alexpage.dev>
Co-authored-by: Aaron Casanova <32409546+aaronccasanova@users.noreply.github.com>

.changeset/healthy-emus-pump.md

@@ -0,0 +1,5 @@
+---
+'@shopify/polaris': patch
+---
+
+Update tokens for border of `Tabs` on hover and pressed state to create better quality interaction.

polaris-react/src/components/Tabs/Tabs.scss

@@ -63,7 +63,7 @@ $item-vertical-padding: $item-min-height * 0.5;
       background-color: transparent;
       // stylelint-disable-next-line selector-max-specificity -- generated by polaris-migrator DO NOT COPY
       &::before {
-        background-color: var(--p-color-border-hover);
+        background-color: var(--p-color-bg-strong-hover);
       }
     }
   }
@@ -73,7 +73,7 @@ $item-vertical-padding: $item-min-height * 0.5;
       background-color: transparent;
       // stylelint-disable-next-line selector-max-specificity -- generated by polaris-migrator DO NOT COPY
       &::before {
-        background: var(--p-color-bg-primary-subdued-active);
+        background-color: var(--p-color-bg-strong-active);
       }
     }
   }

polaris-react/src/components/Tag/Tag.scss

@@ -48,7 +48,7 @@ $button-size: 20px;
     }
 
     &:active {
-      background: var(--p-color-bg-strong-active);
+      background: var(--p-color-bg-strong-hover);
     }
 
     &:disabled {