Fix content blocking

[metasoarous]

Expected behavior:
A user who submits a comment after having connected with social (or who in some other way has been assigned a profile image) should have their image shown next to comments they've submitted. Additionally, these images should show up in the participation visualization.

Actual behavior:
Only a blank box is being displayed next to the comment, and console logs show 500 responses with messages like:

The resource at “https://pbs.twimg.com/profile_images/1369194785269948416/VCAfQJes_normal.jpg” was blocked because content blocking is enabled.

Moreover, no images are shown in the participant visualization.

To Reproduce:
Activate social login on a conversation, submit some comments with that participant, and load conversation from another browser.

Additional context:
Most conversations these days don't use social, so not entirely sure how high of a priority this is, but should probably be fixed nevertheless. It's likely that this had to do with settings that were changed as part of the recent #1758 PR, since this did alter some of the security configuration which might affect this particular behavior.