Merge branch 'errorview-json-fix' into 'develop'

Fix errors in ErrorView

See merge request pleroma/pleroma!3489

CHANGELOG.md

@@ -32,6 +32,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Remote users can no longer reappear after being deleted.
 - Deactivated users may now be deleted.
 - Mix task `pleroma.database prune_objects`
+- Fixed rendering of JSON errors on ActivityPub endpoints.
 - Linkify: Parsing crash with URLs ending in unbalanced closed paren, no path separator, and no query parameters
 
 ### Removed

config/config.exs

@@ -460,7 +460,7 @@ config :pleroma, :shout,
   enabled: true,
   limit: 5_000
 
-config :phoenix, :format_encoders, json: Jason
+config :phoenix, :format_encoders, json: Jason, "activity+json": Jason
 
 config :phoenix, :json_library, Jason