No notification on BYOK key swap

Delvin redirects to the workspace page after a user selects the BYOK plan option. This redirect should provide some notification that it was successful in switching plans since they are moved away from the plan page. Perhaps adding a success message like "Your workspace now only uses the key(s) you provided."

Steps to Reproduce

1. Log in
2. Create a new workspace
3. Create a new provider
4. Click Settings
5. Click Switch to BYOK