[enhancement]: Auto-remove the comma (,) preceding or proceeding {prompt} when the prompt is empty.

### 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?

Under current implementation of prompt templates, if a prompt template has a comma (,) preceding or proceeding {prompt}, it is used as it is even if no prompt is given, altering the image generation slightly. It would be great if it were removed automatically when no additional prompt was given.

### Alternatives

_No response_

### Additional Content

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