[Bug](supernova): not able to add/edit filter by alertName

[IvoGoman]

Description

When I am clicking on the Supernova link on a alert notification in Slack, I am redirected to Supernova and the filter alertname=AlertXYZ is pre-configured from the URL.

However, I am not able to manually set this filter or edit this filter in the UI

Steps to Reproduce

1. Open Supernova
2. Try to filter by alertname
3. No success

Expected Behavior

I would like to be able to add filters based on the alert name in Supernova.

Environment

• OS: [e.g., Windows, macOS, Linux]
• Browser: [e.g., Chrome, Firefox, Safari]
• Version: [e.g., 22]

Additional Context

[IvoGoman]

cc @ArtieReus