Accessibility: Update Close Button component

[Aveline-art]

Overview

As a developer, we need to make sure that our components are accessible as much as humanly possible. For this issue we will update our <CloseButton /> component for accessibility.

Action Items

• [x] Wrap the CloseButton with html tags
• [x] For the <img> tag, add an appropriate alt text (which might be blank, if it is purely decorative)
• [ ] Perform other tasks as needed to ensure accessibility, such as aria labels

Resources/Instructions

3.5 Button