Fix DockerTests for dockerUbi (#91901) (#91905)

kill command was not available. bash -c with kill should be used
relates #91704
closes #91874

Author: pgomulka

qa/os/src/test/java/org/elasticsearch/packaging/test/DockerTests.java

@@ -1107,7 +1107,7 @@ public void test600Interrupt() throws Exception {
             .collect(Collectors.toList());
         int maxPid = processes.stream().map(i -> Integer.parseInt(i.trim())).max(Integer::compareTo).get();
 
-        sh.run("kill -int " + maxPid); // send ctrl+c to all java processes
+        sh.run("bash -c 'kill -int " + maxPid + "'"); // send ctrl+c to all java processes
         final Result containerLogsAfter = getContainerLogs();
 
         assertThat("Container logs should contain stopping ...", containerLogsAfter.stdout, containsString("stopping ..."));