[AppProvider] Disable calt font ligatures (#10871)

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### WHY are these changes introduced?

The Inter font has several configurable font settings. By default,
`calt` ligatures are not disabled. This causes unwanted change in the
presentation of letters to be symbols, e.g., "x" appearing as a multiply
symbol when between numbers like `7x8`. This is a problem for automated
unique identifiers, like Hydrogen deploy hashes in the
`/custom-storefronts` section of the admin:


https://github.com/Shopify/polaris/assets/18447883/e8c4d2a1-9d22-42a7-a585-a158e9dcb1b5

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

### WHAT is this pull request doing?
This PR disables `calt` ligatures in the base styles of the
`AppProvider`.

| Before | After |
|--------|--------|
| <img width="239" alt="Screenshot 2023-10-04 at 2 25 05 PM"
src="https://github.com/Shopify/polaris/assets/18447883/346bc486-866c-4d64-8fd2-1d13bcad8a0c">|
<img width="237" alt="Screenshot 2023-10-04 at 2 24 50 PM"
src="https://github.com/Shopify/polaris/assets/18447883/fc9f8cc4-d3bc-4d86-8ba4-dd466ed1f4ed">
|

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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)

<!--
  Give as much information as needed to experiment with the component
  in the playground.
-->

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

```jsx
import React from 'react';

import {Page, Text} from '../src';

export function Playground() {
  return (
    <Page title="Discounts">
      <Text as="p">xguxh880x9klaslojoffihghgthslohfijkl</Text>
    </Page>
  );
}
```

</details>

### 🎩 checklist

- [ ] Tested on
[mobile](https://github.com/Shopify/polaris/blob/main/documentation/Tophatting.md#cross-browser-testing)
- [x] 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

.changeset/mean-bananas-warn.md

@@ -0,0 +1,5 @@
+---
+'@shopify/polaris': patch
+---
+
+Disabled `calt` font ligatures to prevent unwanted stylizing of letters into symbols

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

@@ -10,6 +10,7 @@ body {
   font-size: var(--p-font-size-325);
   line-height: var(--p-font-line-height-500);
   font-weight: var(--p-font-weight-regular);
+  font-feature-settings: 'calt' 0;
   letter-spacing: initial;
   color: var(--p-color-text);
 }