refactor: remove legacy workflow webview and commands from vse

Description

This MR removes the old duo workflow webview from the VSE codebase since it will no longer be used. Instead everything will move to the panel view.

You can test this by booting running the VSE and verifying the following commands no longer display:

Resolves LSP Issue: #1131

How has this been tested?

This simply moves any existing Duo Workflow commands and moves existing functionality to the Duo Workflow Panel.

This command should no longer display: Show Duo Workflow

Screenshots (if appropriate)

What CHANGELOG entry will this MR create?

• fix: Bug fix fixes - a user-facing issue in production - included in changelog
• feature: New feature - a user-facing change which adds functionality - included in changelog
• BREAKING CHANGE: (fix or feature that would cause existing functionality to change) - should bump major version, mentioned in the changelog
• None - other non-user-facing changes