recent history exchange: Fix mnesia deletion return value

The caller expects this value to either be 'ok' or an error tuple but it
was returning `{atomic,ok}` causing a crash when deactivating this
plugin.

(cherry picked from commit 016697b)

Author: the-mikedavis

deps/rabbitmq_recent_history_exchange/src/rabbit_db_rh_exchange.erl

@@ -142,7 +142,12 @@ delete() ->
        }).
 
 delete_in_mnesia() ->
-    mnesia:delete_table(?RH_TABLE).
+    case mnesia:delete_table(?RH_TABLE) of
+        {atomic, ok} ->
+            ok;
+        {aborted, Reason} ->
+            {error, Reason}
+    end.
 
 delete_in_khepri() ->
     rabbit_khepri:delete(khepri_recent_history_path()).