MM-56358: Unskip racy test TestUploadLicenseFile (#26009)

This was already fixed before in https://github.com/mattermost/mattermost/pull/24971.
We just enable the test now.

https://mattermost.atlassian.net/browse/MM-56358

```release-note
NONE
```

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/jobs/batch_worker_test.go

@@ -14,6 +14,20 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+// TestBatchWorkerRace tests race conditions during the start/stop
+// cases of the batch worker. Use the -race flag while testing this.
+func TestBatchWorkerRace(t *testing.T) {
+	th := Setup(t)
+	defer th.TearDown()
+
+	worker := jobs.MakeBatchWorker(th.Server.Jobs, th.Server.Store(), 1*time.Second, func(rctx *request.Context, job *model.Job) bool {
+		return false
+	})
+
+	go worker.Run()
+	worker.Stop()
+}
+
 func TestBatchWorker(t *testing.T) {
 	createBatchWorker := func(t *testing.T, th *TestHelper, doBatch func(rctx *request.Context, job *model.Job) bool) (*jobs.BatchWorker, *model.Job) {
 		t.Helper()