SummarizingChatReducer_CustomPrompt failed to find expected numbers

https://github.com/dotnet/extensions/blob/cc328a764d1b0200a852772b1f163ebecc7f4a22/test/Libraries/Microsoft.Extensions.AI.Integration.Tests/ChatClientIntegrationTests.cs#L1320-L1357

This test failed because the model decided to summarize the conversation with:
```
So, that's about 40 cans of food per month for your pets!
```

It looks to me like this isn't a "summary" but more of a "response". Perhaps this is due to the brief summarization prompt.