Fix filter for "Discarding message..." logs

The format string is hardcoded as "~s~n" in
[ERTS](https://github.com/erlang/otp/blame/OTP-26.0/erts/emulator/beam/utils.c#L878).
Using unicode modifier resulted in a mismatch.

(cherry picked from commit f43d204)

Author: gomoripeti

deps/rabbit/apps/rabbitmq_prelaunch/src/rabbit_prelaunch_early_logging.erl

@@ -76,7 +76,7 @@ add_primary_filters() ->
 
 filter_discarded_message(#{level := error,
                            meta := #{error_logger := #{emulator := true, tag := error}},
-                           msg := {"~ts~n", Msg}}, OnMatch) ->
+                           msg := {"~s~n", Msg}}, OnMatch) ->
     case string:find(Msg, "Discarding message") of
         nomatch ->
             ignore;