Remove max-width from Lede (Shopify#10449)

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### WHY are these changes introduced?

Fixes Shopify#10154 <!-- link to issue
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This change matches what is currently on prod

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### How to 🎩

🖥 [Local development
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import React from 'react';
import {Page} from '../src';

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### 🎩 checklist

- [ ] Tested on
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- [ ] Tested on [multiple
browsers](https://help.shopify.com/en/manual/shopify-admin/supported-browsers)
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[accessibility](https://github.com/Shopify/polaris/blob/main/documentation/Accessibility%20testing.md)
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documentation](https://github.com/Shopify/polaris/blob/main/documentation/Tophatting%20documentation.md)
changes in the style guide

polaris.shopify.com/src/components/Lede/Lede.module.scss

@@ -4,7 +4,6 @@
     font-size: var(--font-size-600);
     font-weight: var(--font-weight-500);
     letter-spacing: var(--letter-spacing-300);
-    max-width: 60ch;
     margin-bottom: 1.5rem;
   }
 }