Projects not fully created during onboarding.

### Environment

SaaS (https://sentry.io/)

### Steps to Reproduce

1. Open Sentry issues feed page while having access to any project (New organisation, just joined, not member of a team...).
2. Click on "Create project"
3. Choose a platform and name
4. Click "create project"
5. Go back using the browser back button or "Back to platform selection"

### Expected Result

The UI shows a confirmation in the UI saying "Created Project [NAME]", which makes the user believe that the project is fully created.

The user follows the UI to configure the SDK and clicks back to platform selection to create a new project, or simply go back to create a second project.

The expectation here is that the project is created in Sentry.

### Actual Result

When going back, Sentry silently deletes the project with message "Removed project new-pro in getting_started" and attributes the action to the user, see screenshot:

This creates a negative UX as the UI shows the project is created but no signs that the same project was automatically deleted.

### Product Area

Projects - Project Creation

### Link

_No response_

### DSN

_No response_

### Version

_No response_