Update JIT SSO setup to use WorkOS Organization ID

[mintlify]

Summary

Updates the Just In Time (JIT) SSO setup instructions in the role-based access control guide to reflect the new configuration flow. Admins now enter a WorkOS Organization ID directly in the SSO settings tab instead of clicking a "Set Up" button to launch an OAuth login flow.

Source PR

porter-dev/code#5451 replaces the WorkOS OAuth integration flow with manual organization ID configuration. Admins enter their WorkOS Organization ID in the SSO settings UI, and the configuration is saved alongside the default role for newly provisioned users.

Changes

• Replaced the OAuth "Set Up" / "Update Provider" steps with instructions for entering a WorkOS Organization ID and selecting a default role.
• Added an example organization ID format (org_ABC123ABC123ABC123ABC123AB) and a pointer to find this value in the WorkOS dashboard.
• Updated the follow-up guidance for connecting a different organization to reflect that this is now done by editing the same input field.