[kafka-consumer] Use wait group to ensure goroutine is finished befor…

…e returning from Close (#4582)

## Which problem is this PR solving?
Resolves # [4576](#4576)

## Short description of the changes
Once we call
[start](https://github.com/jaegertracing/jaeger/blob/main/cmd/ingester/app/consumer/consumer.go#L76)
and call
[close](https://github.com/jaegertracing/jaeger/blob/main/cmd/ingester/app/consumer/consumer.go#L76)
again with fxtest module, there is a chance that the application will
close the goroutine before the
l[ogline](https://github.com/jaegertracing/jaeger/blob/main/cmd/ingester/app/consumer/consumer.go#L79)
is executed causing **panic Log in routine after .. has completed**.

Fix:
Add a wait group that will wait for the goroutine to finish before
closing the channel.

---------

Signed-off-by: kennyaz <115052215+kennyaz@users.noreply.github.com>

cmd/ingester/app/consumer/consumer.go

@@ -75,7 +75,9 @@ func New(params Params) (*Consumer, error) {
 // Start begins consuming messages in a go routine
 func (c *Consumer) Start() {
 	c.deadlockDetector.start()
+	c.doneWg.Add(1)
 	go func() {
+		defer c.doneWg.Done()
 		c.logger.Info("Starting main loop")
 		for pc := range c.internalConsumer.Partitions() {
 			c.partitionMapLock.Lock()

cmd/ingester/app/consumer/consumer_test.go

@@ -79,6 +79,7 @@ func newSaramaClusterConsumer(saramaPartitionConsumer sarama.PartitionConsumer,
 	saramaClusterConsumer.On("Partitions").Return((<-chan cluster.PartitionConsumer)(pcha))
 	saramaClusterConsumer.On("Close").Return(nil).Run(func(args mock.Arguments) {
 		mc.Close()
+		close(pcha)
 	})
 	saramaClusterConsumer.On("MarkPartitionOffset", mock.Anything, mock.Anything, mock.Anything, mock.Anything).Return(nil)
 	return saramaClusterConsumer