Redis healthcheck message sometimes is not useful.

[OscarRL]

Describe the bug

There is some runtime exceptions that has no message when they are fired.

Actually the healthcheck performs a message with
return builder.down().withData("reason", "client [" + client.getKey() + "]: " + e.getMessage()).build();

Expected behavior

Reason should include a message that must explain what's happening on any exception.

Actual behavior

If getMessage() returns null the message is something like

"reason": "client [<default>]: null"

How to Reproduce?

1. Setup a 1 second timeout.
2. Connect to a redis that is lagging or with high workload.
3. Wait to a healthcheck happend.
4. Read the healthcheck message.

In this reproducer the atMost method of Mutiny will throw a TimeoutException that has no message ( null ).

Output of uname -a or ver

No response

Output of java -version

No response

GraalVM version (if different from Java)

No response

Quarkus version or git rev

No response

Build tool (ie. output of mvnw --version or gradlew --version)

No response

Additional information

No response

[quarkus-bot]

/cc @cescoffier, @gsmet, @jmartisk, @machi1990, @xstefank