Dashboard page served from /billing url

### Current Behavior

When a dashboard-only user views a team they are shown the 'list of dashboards in this team' page.

However, the url is `/team//billing`. This is likely due to competing checks causing a redirect to the billing page, but then showing the dashboard list as that's all the user has permission for.

This has caused support confusion when a Dashboard user reported #5807 , but the url they were reporting was `/billing` - it took a couple exchanges before I realised they were a dashboard-only user and seeing a completely different page to what I could see.

The dashboard list should be on a dedicated route - and be accessible to any user (although not suggesting adding it to the navigation menu).

### Expected Behavior

Dashboard user is redirected to `/team//dashboards` to see the list of dashboards.

Any user can manually navigate to the same page.

### 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