remove timestamp, it seems it's not present for all messages?

src/sysalert/email.py

@@ -52,7 +52,7 @@ def failure(name, failures, config):
     reader.add_match(_SYSTEMD_INVOCATION_ID=latest_inv_id)
     journal_txt = "\n".join(
             [
-                f'{entry["_SOURCE_REALTIME_TIMESTAMP"]}: {entry["MESSAGE"]}'
+                entry["MESSAGE"]
                 for entry in list(reader)[-200:]
             ])