2.x Uploaded image increases in size and ignores image: false

## To Reproduce
Upload any image file through the Apostrophe UI.

## Expected behavior

I would like to upload image files without any modifications, optimisations or compressions. I would like to eventually use it as follows: `{{ apos.attachments.url(data.widget._backgroundImage.attachment, { size: 'original' }) }}`

## Describe the bug
However, when I upload a 300KB JPG file, I get the "original" file with 1.7MB in size.

## Details

**Version of Node.js:**
v14.17.0

**Server Operating System:**
MacOS Catalina

**Additional context:**

`apostrophe-attachments` configuration
```
'apostrophe-attachments': {
svgImages: true,
fileGroups: [
{
name: 'images',
label: 'Images',
extensions: ['png', 'gif', 'jpg', 'svg'],
extensionMaps: { jpeg: 'jpg' },
image: false
},
```

👆 Notice that there is `image: false`, so it should not treat it as an image and hence not created scaled versions of the file.

I am not using ImageMagic – I am going to try and give an update if it helps.

**Screenshots**
Original file:

File on the server (with the scaled image versions too):

Start with the apostrophe-attachments configuration and the upload path that handles the `image: false` option. Reproduce the upload using a JPG and the `size: 'original'` URL, then verify that the original file is unchanged and that scaled image versions are not created when image processing is disabled.

Written by the indexing model from the issue text.