Design: Explain vuln to GA

Overview

As part of maturing Explain Vulnerability to GA, we're incorporating with GitLab Duo Chat. As part of this transition, we are removing the following from this AI card in the vulnerability description page:

• description
• link to feedback issue
• option to send code with prompt
• pre-flight security check
• prompt preview

When we move Explain Vuln and Resolve Vuln to GA, unfortunately, GitLab Duo chat won't yet be context aware, so typing in something like "What is this vulnerability?" in the chat won't work.

Proposal

• Convert the primary button for Vulnerability resolution into a split button including both Vulnerability resolution and Vulnerability explanation.
• When the user initiates Vulnerability explanation (by way of 1. Clicking on the Explain vulnerability button, 2. by clicking on the linked text under the Description header, or 3. typing /vulnerability_explain into GitLab Duo Chat), the chat shows a blue bubble with /vulnerability_explain at the top to teach the user that this is an available slash command.

See designs below.