Allow ImageMagic to resize all image types supported by Design Management on Sidekiq servers
### Problem
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/22860 introduced the ability for design images to be resized.
When enabling the `design_management_resize_images` feature flag on staging:
- `gif`, `bmp`, `ico`, and `png` files are processed without error
- `jpg` and `tiff` images produce the following error in [Sentry](https://sentry.gitlab.net/gitlab/staginggitlabcom/issues/1348897/?query=is:unresolved%20NewVersionWorker):
```
Failed to manipulate with MiniMagick, maybe it is not an image?
Original Error: `gm identify /tmp/mini_magick20200223-16295-1vw9peo` failed with error: gm identify: No decode delegate for this image format (/tmp/mini_magick20200223-16295-1vw9peo). gm identify: Request did not return an image.
```
### Proposal
Allow the ImageMagick library on our Sidekiq servers to process all files that are supported by design management (besides `image/svg+xml`!):
- `image/png`
- `image/jpeg`
- `image/bmp`
- `image/gif`
- `image/tiff`
- `image/ico`
The above [Sentry error](https://sentry.gitlab.net/gitlab/staginggitlabcom/issues/1348897/?query=is:unresolved%20NewVersionWorker) suggests the issue happens when running the command `gm identify <path/to/image>`. `gm identify` is part of [`GraphicsMagick` library](http://www.graphicsmagick.org/identify.html).
### References
- [Sentry error](https://sentry.gitlab.net/gitlab/staginggitlabcom/issues/1348897/?query=is:unresolved%20NewVersionWorker)
- https://gitlab.com/gitlab-org/gitlab/-/merge_requests/22860
issue