bug: num sources displayed should correspond to total sources

## Expected Changes
- For a single asset, we should display the total number of sources that are actively pushing data for it and not just the ones aggregated in the latest `100ms` bucket (which is what is returned by the multi stream endpoint)

<img width="1087" alt="Image" src="https://github.com/user-attachments/assets/af752ca9-7960-4338-952f-2333b51d9397" />