Separation `confirm_img_paste` is required to `img_name_func` and confirm message

### 🚀 The feature, motivation and pitch

In current, Entering Y or N must be done after entering the file name.
`confirm_img_paste = false` disables both entering file name and confirm message.

If I set `img_name_func = nil` to enter filename manually and ignore confirm message,
the default location of image set to default folder (asset/img)
When `img_name_func` is set to change location which image is downloaded, I can't set `confirm_img_paste` independently.

I suggest to separate `confirm_img_paste` for `img_name_func` and confirm message.

### Alternatives

_No response_

### Additional context

_No response_