Trial ribbon missing corners on create-team page

### Current Behavior

The new team selection page for users without a team looks like this - with a red ribbon highlighting the free trial


If a user picks the trial option, the next page lets them enter team name/description and displays the team type tile. However the red ribbon on this page is missing its corners:

### Expected Behavior

Ribbon to have its corners

### Steps To Reproduce

_No response_

### Environment

- FlowFuse version:
- Node.js version:
- npm version:
- Platform/OS:
- Browser:

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate