[minor] alliance[object Object] class on Audience Display bracket

### Possibly not a bug. But, doesn't seem *quite* right to me. :)

**Describe the bug**
No impact to users. When viewing the bracket on the audience display, certain elements have the CSS class `alliance[object Object]`.

**To Reproduce**
Steps to reproduce the behavior:
1. Open an audience display and display the bracket/pit display in playoffs
2. Inspect the DOM (i.e. open DevTools)
3. Observe the CSS classes of the bracket elements

**Expected behavior**
Elements should have proper CSS classes -- *maybe* possibly affecting styles in some minor way?

**Screenshots**

**Device (please complete the following information):**
- OS: macOS 15.4.1 (24E263)
- Browser: Firefox 137.0.1 (aarch64)
- FTCLive v6.6.1

Reproduce the issue by opening an audience display, showing the playoff bracket or pit display, and inspecting the DOM. Trace where the bracket element CSS class is assembled; done means the affected elements have proper class names rather than containing `[object Object]`.

Written by the indexing model from the issue text.