[Event Hubs] Re-enable samples testing (#31347)

Addresses https://github.com/Azure/azure-sdk-for-js/issues/30580

Live run:
https://dev.azure.com/azure-sdk/internal/_build/results?buildId=4211884&view=results

sdk/eventhub/event-hubs/tests.yml

@@ -6,7 +6,6 @@ extends:
       PackageName: "@azure/event-hubs"
       ServiceDirectory: eventhub
       MatrixFilters:
-        - TestType=^(?!sample).*
         - DependencyVersion=^$
       UseFederatedAuth: true
       Clouds: 'Public,Canary'