Agent Builder vs Playground : Token count behavior diff

Hi There,

An Azure OpenAI model has been registered as Custom.

It works in both Agent Builder and Playground.

In Agent Builder it says `Token used: nnn`, where nnn is the actual token count from the usage SSE event. E.g 
```
“usage”: {  “completion_token”: 123 }
```

In Playground, however, it says: “This model doesn’t return token count.” 