llava: remove prog parameter from ArgumentParser

This commit removes the `prog` parameter from `ArgumentParser`
so that it uses the default value which is the name of the script.

The motivation for this change is that currently the usage output looks
like this:
```console
$ python examples/llava/convert-image-encoder-to-gguf.py --help
usage: convert_hf_to_gguf.py [-h] ...
```
And with this change it will look like this:
```console
$ python examples/llava/convert-image-encoder-to-gguf.py --help
usage: convert-image-encoder-to-gguf.py [-h] ...
```

Signed-off-by: Daniel Bevenius <[email protected]>

examples/llava/convert-image-encoder-to-gguf.py

@@ -71,7 +71,7 @@ def bytes_to_unicode():
     return dict(zip(bs, cs))
 
 
-ap = argparse.ArgumentParser(prog="convert_hf_to_gguf.py")
+ap = argparse.ArgumentParser()
 ap.add_argument("-m", "--model-dir", help="Path to model directory cloned from HF Hub", required=True)
 ap.add_argument("--use-f32", action="store_true", default=False, help="Use f32 instead of f16")
 ap.add_argument("--text-only", action="store_true", required=False,