Image Picka doesn't use referrerpolicy from the image if there is a link detected.

[eight04]

To Reproduce Steps to reproduce the behavior:

1. Enable Detect images from links option
2. Create a page with an <a> to the image and an <img> of the image.
3. Add referrerpolicy to <img>
4. Batch download

Since two URLs are the same, one is removed, including the information of referrerpolicy.

We should use a better method to decide which should be removed.

Expected behavior Image Picka should download the image correctly.

Environments (please complete the following information):

• OS: Windows 10
• Browser: Firefox Nightly 123.0a1
• Extension Version: 0.17.0