Multiple Source Failed Fetch for Sonarr/Radarr Tags

### Description

Background: Sometimes a movie or TV show is requested through Seerr (via Plex watchlist), and other times, I as the server owner add them manually in Radarr or Sonarr (with a tag of "manuallyadded").

Therefore I am wanting to make a collection with the following sources:
1. Seerr Requests (Server Owner Requests); and
2. Sonarr/Radarr Tags (items in Sonarr/Radarr with "manuallyadded" tag)

When I create a collection with the above sources, Agregarr only pulls the items from my Seerr requests and returns an error with radarr or sonarr items with the "manuallyadded" tag.

I tried troubleshooting the issue by doing the following:
1. Add only a single source pointing to my Sonarr/Radarr instance. This successfully pulls the items with the tag, but as soon as I add Seerr as a second source it only provides the Seerr items.
2. I rearranged the order of the sources
3. Switched Combine Mode between all 4 options,
4. Increased the Max Items to 100
5. Restart Agregarr container
6. Re-test Sonarr/Radarr instance

### Version

2.4.1

### Steps to Reproduce

1. Go to 'Home'
2. Click 'Add Collection'
3. Select Collection Type 'Multiple Sources'
4. Click 'Add Source'
5. Source 1: Source Type 'Seerr Requests', Collection Sub-Type 'Server Owner requests'
6. Click 'Add Source'
7. Source 2: Source Type 'Sonarr Tags', Sonarr instance 'Sonarr (default)', Sonarr Tag 'manuallyadded'
8. Set Combine Mode to any 4 of Interleaved, List Order, Randomised, Cycle Lists'
9. Set Library Selection to 'TV Shows (Server)'
10. Leave all other items as default options
11. Click 'Preview Collection'
12. The result is only the Seerr requests and nothing with the Sonarr tags
13. Repeat the same using Radarr tags and the same issue persists

### List Links

_No response_

### Screenshots

### Logs

```shell
Sonarr error when using multiple sources:
2026-03-05T23:45:57.384Z [error][Collections Preview API - Multi-Source]: Failed to fetch from Sonarrtag: {"sourceId":"source-1772754103193","sourceType":"sonarrtag","sourceDisplayName":"Sonarrtag","error":"[object Object]"}

Radarr error when using multiple sources:
2026-03-05T23:39:12.038Z [error][Collections Preview API - Multi-Source]: Failed to fetch from Radarrtag: {"sourceId":"source-1772753937041","sourceType":"radarrtag","sourceDisplayName":"Radarrtag","error":"[object Object]"}
```

### Additional Context

_No response_