az repos requires user authentication despite successfull az login

### **This is autogenerated. Please review and update as needed.**

## Describe the bug

**Command Name**
`az repos pr list
Extension Name: azure-devops. Version: 1.25.7.`

**Errors:**
```
The requested resource requires user authentication: https://dev.azure.com/MYPROJECT/some-guid/_apis/git/repositories/another-guid/pullRequests?searchCriteria.includeLinks=False
```

## To Reproduce:
Steps to reproduce the behavior. Note that argument values have been redacted, as they may contain sensitive information.

- `az login` (succesfully display output)
- `az repos pr list`

## Expected Behavior
list the pr of the MYPROJECT

## Environment Summary
```
Windows-10-10.0.18362-SP0
Python 3.6.6
Installer: MSI

azure-cli 2.5.0 *

Extensions:
azure-devops 1.25.7

```
## Additional Context