[fix][test] Fix flaky test ResourceGroupUsageAggregationTest. testProduceConsumeUsageOnRG

[Technoboy-]

Fixes #17120
Master Issue: #17120

Motivation

The failure assertion is at line 206 :

Assert.assertEquals(recvdNumMsgs, topicStats.msgOutCounter);

recvdNumMsgs must be 10, but topicStats.msgOutCounter is from broker side, coming from dispatcher :

writeAndFlushPromise.addListener(status -> {
            // only increment counters after the messages have been successfully written to the TCP/IP connection
            if (status.isSuccess()) {
                msgOut.recordMultipleEvents(totalMessages, totalBytes);
                msgOutCounter.add(totalMessages);
                bytesOutCounter.add(totalBytes);
                chunkedMessageRate.recordMultipleEvents(totalChunkedMessages, 0);
            }
        });

So we need to use Awaitility for that assertion.

Modification

• Remove for block, use Map.get.
• Add cleanup logic in order to run the test many times.

Documentation

• doc-not-needed
  (Please explain why)