Fix APP_URL not updating to HTTPS after SSL certification

[mehrancodes]

Problem

When SSL certification is enabled for a site, Forge doesn't automatically update the APP_URL environment variable from http:// to https:// format.

Solution

• Modified the pipeline to conditionally add APP_URL with proper HTTPS protocol when SSL is enabled
• Created a dedicated Action class to handle environment variable updates (App\Actions\Forge\UpdateForgeEnvironmentVariables)
• Refactored for better separation of concerns and testability

This ensures that Laravel applications correctly detect HTTPS after SSL certification is enabled.