[A11Y] Clickable elements should have interactive semantics

[softvision-oana-arbuzov]

Browser / Version: Firefox Nightly 82.0a1 (2020-09-17) Operating System: Windows 10 Pro

Steps to Reproduce:

1. Navigate to https://webcompat.com/issues/new
2. Fill in all required info until reaching "What is wrong with the page" section.
3. Observe categories.

Expected Behavior: Categories have interactive semantics.

Actual Behavior: Categories don't have interactive semantics.

Notes:

1. Screenshot attached.

2. The issue is also reproducible for:

• browsers

• navigation bullets from "What is a web compatibility issue?" popup

• "X" button from "What is a web compatibility issue?" and "Public Reports" popups

• report via GitHub icon

2. Read more about it here: https://developer.mozilla.org/en-US/docs/Web/Accessibility/Understanding_WCAG/Keyboard

Watchers: @softvision-oana-arbuzov @cipriansv