Manually Trigger Engine Pool Refresh that's From URI

**Is your feature request related to a problem? Please describe.**
I'm using the prediction engine pool from a URI as such:

```
services.AddPredictionEnginePool().FromUri(
uri: $"{URI}",
period: TimeSpan.FromMinutes(5));
```

Which is working great. However, I'd like to be able to get the engine pool updated on demand, rather than waiting up to 5 minutes for it to refresh itself.

**Describe the solution you'd like**
Perhaps a method on the `PredictionEnginePool` class that allows for a refresh i.e. `predictionEnginePool.RefreshFromUri()`

**Describe alternatives you've considered**
Can certainly shorten the period, but it seems unnecessary to have it checking every 30 seconds when I know exactly when it needs to update.

It could also be a local file using `FromFile` but the model lives elsewhere and I'd like it to stay that way.

**Additional context**
Is this something that has been explored at all? I'm not opposed to taking a stab at it but want to make sure it's not something that's already been discussed/attempted/etc.