System.NullReferenceException: Object reference not set to an instance of an object.

Sentry Issue: [UNITY-EXPLORER-PDX](https://decentraland.sentry.io/issues/7580633362/)

```
System.NullReferenceException: Object reference not set to an instance of an object.
File "C:/workspace/workspace/p/Explorer/Assets/DCL/Infrastructure/SceneRuntime/Apis/Modules/SignedFetch/Messages/FlatFetchResponse.cs", line 37, in .ctor
File "C:/workspace/workspace/p/Explorer/Assets/DCL/Infrastructure/SceneRuntime/Apis/Modules/SignedFetch/SignedFetchWrap.cs", line 257, in MoveNext
File "C:/workspace/workspace/p/Explorer/Assets/DCL/WebRequests/ArtificialDelayWebRequestController.cs", line 34, in MoveNext
File "C:/workspace/workspace/p/Explorer/Assets/DCL/WebRequests/DebugMetricsWebRequestController.cs", line 34, in MoveNext
File "C:/workspace/workspace/p/Explorer/Assets/DCL/WebRequests/WebRequestController.cs", line 63, in MoveNext
...
(50 additional frame(s) were not displayed)

System.AggregateException: A Task's exception(s) were not observed either by Waiting on the Task or accessing its Exception property. As a result, the unobserved exception was rethrown by the finalizer thread.
```
This issue was automatically created by Sentry via [Explorer Alpha Github Issue Creation](https://sentry.io/organizations/decentraland/monitors/alerts/3130340/)

Start with Assets/DCL/Infrastructure/SceneRuntime/Apis/Modules/SignedFetch/Messages/FlatFetchResponse.cs at line 37, then follow the call chain through SignedFetchWrap.cs line 257 and the web request controllers named in the trace. Use the linked Sentry issue to identify the triggering response and confirm the completed change no longer produces the reported NullReferenceException or an unobserved task exception.

Written by the indexing model from the issue text.