JS Error when installiing Github integration

### Environment

self-hosted (https://develop.sentry.dev/self-hosted/)

### Steps to Reproduce

1. Setup Self Hosted Sentry
2. Add GitHub App
3. Add Github Config to sentry/config.yml
4. Klick on the installation button at the github integration

### Expected Result

Open the installation Step and have the integration running

### Actual Result

I only see a loading screen and i have an Error in my JS Console

```
Uncaught (in promise) TypeError: can't access property "tracePropagationTargets", o is undefined
M initializeSdk.tsx:104
e8 initializePipelineView.tsx:17
index.tsx:3
```

i can see the Request at my server logs but no error in the logs

```
window.__initialData
```
this is also empty

### Product Area

Settings - Integrations

### Link

_No response_

### DSN

_No response_

### Version

25.12.1

Reproduce the self-hosted GitHub integration installation flow and inspect the reported stack entries in initializeSdk.tsx, initializePipelineView.tsx, and index.tsx. Check why tracePropagationTargets is accessed from an undefined value and whether window.__initialData is populated during the request. Done means the installation step opens without the JavaScript error and the integration can proceed.

Written by the indexing model from the issue text.