BUG: Object reference not set.... .net 6 functions

**Describe the issue**
When using this library in a new Azure Functions project (.net6, runtime V4) it works locally but not on Azure.

`Object reference not set to an instance of an object.`

**To Reproduce**
1. Create new Azure functions project with .Net 6
2. Add a new project without dependencies and reference it in your functions project
3. Deploy to Azure
4. Call `/api/swagger.json`

**Expected behavior**
I expect that swagger would just work like it does locally.

**Screenshots**


**Environment (please complete the following information, if applicable):**
- OS: Azure (Windows Service plan, `FUNCTIONS_EXTENSION_VERSION` = `~4`, `FUNCTIONS_WORKER_RUNTIME` = `dotnet`)
- Version `1.0.0` (nuget)