Fixes/do not override timestamps (#7336)

* Revert "Fixes/do not override timestamps (#7331)"

This reverts commit 581a5c9d29.

* Document Snowflake ID corner-case a bit more

Snowflake IDs are used for two purposes: making object identifiers harder to
guess and ensuring they are in chronological order. For this reason, they
are based on the `created_at` attribute of the object.

Unfortunately, inserting items with older snowflakes IDs will break the
assumption of consumers of the paging APIs that new items will always have
a greater identifier than the last seen one.

* Add `override_timestamps` virtual attribute to not correlate snowflake ID with created_at

app/lib/activitypub/activity/announce.rb

@@ -16,6 +16,7 @@ class ActivityPub::Activity::Announce < ActivityPub::Activity
       reblog: original_status,
       uri: @json['id'],
       created_at: @json['published'],
+      override_timestamps: @options[:override_timestamps],
       visibility: original_status.visibility
     )