Drop log level of header limits log message

Especially when using in-memory logging, these are too noisy so
let's drop them back to debug level.

(cherry picked from commit afc47ee)

Related: RHEL-33890

src/journal/journald-server.c

@@ -848,8 +848,9 @@ static void write_to_journal(Server *s, uid_t uid, struct iovec *iovec, size_t n
                 if (!f)
                         return;
 
-                if (journal_file_rotate_suggested(f->file, s->max_file_usec, LOG_INFO)) {
-                        log_info("%s: Journal header limits reached or header out-of-date, rotating.", f->file->path);
+                if (journal_file_rotate_suggested(f->file, s->max_file_usec, LOG_DEBUG)) {
+                        log_debug("%s: Journal header limits reached or header out-of-date, rotating.",
+                                  f->file->path);
                         rotate = true;
                 }
         }