[enhancement]: Positive Prompt History Size

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Contact Details

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### What should this feature add?

Is it possible to increase the prompt history, as I'm finding it to be a bit short, particularly on large pieces of work.
Is it as simple as adjusting this value, perhaps?

(It would be nice in a setting or parameter somewhere though!)

https://github.com/invoke-ai/InvokeAI/blob/3fdceba5fc6993d9f66a608cd116e0180743d819/invokeai/frontend/web/src/features/controlLayers/store/types.ts#L560

### Alternatives

_No response_

### Additional Content

_No response_