[EXT] Add DisplayLG text variant from design-tokens

### **Description**

We need to add a `DisplayLG` typography token to the extension repository. This token will be used across the design system for large display typography, ensuring consistency in the typographic styles for larger screens.

### **Technical Details**

- Create a new `DisplayLG` typography token in the extension repository.
- Reference the following resources for the specific typography styles:
- Figma File: [DS Typography / Large Screen](https://www.figma.com/design/likmuA72JatXDKDChibHBG/DS-Typography-%2F-Large-Screen?node-id=0-1&t=QhahIunb9CH4PfFL-1)
- Figma File: [DS Typography / Small Screen](https://www.figma.com/design/Na8UKll7g12UywIPGEVLvX/DS-Typography-%2F-Small-Screen?m=auto&node-id=0-1&t=2EAwp5DP5nWGUTbK-1)
- Insight Report: [Typography Audit](https://www.figma.com/design/MObd9JM3xkqwD4wHu7I5DX/Typography-Audit?node-id=0-1&t=09x3QsgwDSrtwOTj-1)

### **Acceptance Criteria**

- Add the `DisplayLG` typography token with the correct styling for large screens based on the Figma design files.
- Validate the new token across different platforms to ensure consistency in typography rendering.
- Update documentation

### **References**

- Design Ticket: [MetaMask Planning Issue #3244](https://app.zenhub.com/workspaces/design-system-61e8a2ae77c3a60012e5003c/issues/gh/metamask/metamask-planning/3244)
- Figma File: [DS Typography / Large Screen](https://www.figma.com/design/likmuA72JatXDKDChibHBG/DS-Typography-%2F-Large-Screen?node-id=0-1&t=QhahIunb9CH4PfFL-1)
- Figma File: [DS Typography / Small Screen](https://www.figma.com/design/Na8UKll7g12UywIPGEVLvX/DS-Typography-%2F-Small-Screen?m=auto&node-id=0-1&t=2EAwp5DP5nWGUTbK-1)
- Insight Report: [Typography Audit](https://www.figma.com/design/MObd9JM3xkqwD4wHu7I5DX/Typography-Audit?node-id=0-1&t=09x3QsgwDSrtwOTj-1)

Start by locating the existing typography tokens in the MetaMask extension repository, then compare their structure with the DS Typography / Large Screen and Small Screen Figma files and the Typography Audit. The work is done when DisplayLG has the specified large-screen styling, is validated across platforms, and the relevant documentation is updated.

Written by the indexing model from the issue text.