Design widget - Allow user to upload a design

What does this MR do and why?

Allow user to upload a design on an Issue work item through upload button.

This does not include Drag & Drop.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

How to set up and validate locally

1. Visit an issue type work item.
2. Click on Add design button.
3. Upload a design.

Related to #456077 (closed)