upload:// leaks into emails

[setharnold]

Bug Description

Hello, I get emails for some Discourse content. A lot of the links in the emails are broken, they'll be of the form: upload://XXXXXXXXXXXXXXXXXXXXXXXXXXX.png or similar.

One that I got recently on a public post is https://discourse.ubuntu.com/t/we-need-to-revisit-the-first-visit-experience/40889/

![image|800x716](upload://ct8nVSNr5AM0Q82hFxa7SQX1vJu.png)

Because these aren't useful, I would rather they be replaced with a link to the image or whatever other content was embedded.

Thanks

It seems to happen across many of our Discourse sites:

$ rg -c -l upload:// 
imaps:[email protected]:993/web-and-design-discourse-canonical-com/iterations/1350509886-1:7
imaps:[email protected]:993/web-and-design-discourse-canonical-com/iterations/1350509886-2:11
imaps:[email protected]:993/engineering-discourse-canonical-com/foundations/1350509894-1:1
imaps:[email protected]:993/engineering-discourse-canonical-com/foundations/1350509894-3:1
imaps:[email protected]:993/engineering-discourse-canonical-com/foundations/1350509894-2:1
imaps:[email protected]:993/engineering-discourse-canonical-com/announcements/1350509888-25:1
imaps:[email protected]:993/engineering-discourse-canonical-com/announcements/1350509888-46:1
imaps:[email protected]:993/engineering-discourse-canonical-com/announcements/1350509888-12:1
imaps:[email protected]:993/content-discourse-canonical-com/announcements/1350509967-2:1
imaps:[email protected]:993/content-discourse-canonical-com/announcements/1350509967-1:1
imaps:[email protected]:993/discourse-ubuntu-com/site-feedback/1350509969-7:5
imaps:[email protected]:993/communications-and-content-discourse-canonical-com/announcements/1350509986-1:1
imaps:[email protected]:993/discourse-canonical-com/announcements/1350509946-5:1
imaps:[email protected]:993/discourse-canonical-com/announcements/1350509946-15:1
imaps:[email protected]:993/discourse-canonical-com/engineering/1350509873-6:1
imaps:[email protected]:993/discourse-canonical-com/engineering/1350509873-2:3

To Reproduce

N/A

Environment

N/A

Relevant log output

N/A

Additional context

No response