Setting factory on the `OpenTracingTest' to be removed

[Paolo Patierno]

Currently we are setting a default OpenTracing factory at this line

https://github.com/strimzi/strimzi-kafka-bridge/blob/main/src/test/java/io/strimzi/kafka/bridge/tracing/OpenTracingTest.java#L26

It can be removed when Vert.x 4.3.4 is out, because of this fix eclipse-vertx/vertx-tracing#45
This way the OpenTracing test will align with the OpenTelemetry test.