Fix bug for non routed websocket requests

[Feiko]

Description

Added a null check when handling a non routed webserver request

Motivation and Context

Webserver does not work together with Websocketserver for non routed requests. So when no controller is used.

How Has This Been Tested?

With websocketserver. Same change was already done for routed requests.

Screenshots

Types of changes

• Improvement (non-breaking change that improves a feature, code or algorithm)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Config and build (change in the configuration and build system, has no impact on code or features)
• Dependencies (update dependencies and changes associated, has no impact on code or features)
• Unit Tests (work on Unit Tests, has no impact on code or features)
• Documentation (changes or updates in the documentation, has no impact on code or features)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[josesimoes]

LGTM