[bugfix] concurrent map writes in dereferencer media processing maps (#2964)

* removes the avatar / header deref maps as we now have per-uri status / account locks, adds retries on data-races, adds separate emoji map mutex

* work with a copy of account / status for each retry loop

* revert to old data race behaviour, it gets too complicated otherwise

---------

Co-authored-by: tobi <tobi.smethurst@protonmail.com>

internal/federation/dereferencing/status.go

@@ -285,7 +285,7 @@ func (d *Dereferencer) enrichStatusSafely(
 	requestUser string,
 	uri *url.URL,
 	status *gtsmodel.Status,
-	apubStatus ap.Statusable,
+	statusable ap.Statusable,
 ) (*gtsmodel.Status, ap.Statusable, bool, error) {
 	uriStr := status.URI
 
@@ -313,7 +313,7 @@ func (d *Dereferencer) enrichStatusSafely(
 		requestUser,
 		uri,
 		status,
-		apubStatus,
+		statusable,
 	)
 
 	if gtserror.StatusCode(err) >= 400 {