test: bump test broker to apachepulsar/pulsar:4.2.2

4.2.2 is the latest 4.x release and includes the null-value compaction
fix (apache/pulsar#25817, shipped in release/4.2.2). This lets
test_null_value_compaction pass; 4.0.0 predated the fix.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: grishaf

build-support/pulsar-test-service-start.sh

@@ -25,7 +25,7 @@ cd $SRC_DIR
 
 ./build-support/pulsar-test-service-stop.sh
 
-CONTAINER_ID=$(docker run -i --user $(id -u) -p 8080:8080 -p 6650:6650 -p 8443:8443 -p 6651:6651 --rm --detach apachepulsar/pulsar:4.0.0 sleep 3600)
+CONTAINER_ID=$(docker run -i --user $(id -u) -p 8080:8080 -p 6650:6650 -p 8443:8443 -p 6651:6651 --rm --detach apachepulsar/pulsar:4.2.2 sleep 3600)
 echo $CONTAINER_ID > .tests-container-id.txt
 
 docker cp tests/test-conf $CONTAINER_ID:/pulsar/test-conf