Cleaned up UI Bench yaml and browsing providers on 5.2.5 

Cleaned up ui_bench_test.yaml.template and added 5.2.5 support for browsing providers.
We tend to stretch this to multiple lines for readability, eg.:
```python
link_marker = version.pick({
    version.LOWEST: "ext_management_system",
    "5.2.5": "ems_infra"
})
```