Skip known flaky queue tests on CI environment (#24419)

Random CI failures are annoying. It's better to just skip the affected
tests so maintainers can use their valuable time for more productive
topics.

Related: https://github.com/go-gitea/gitea/issues/23608
Related: https://github.com/go-gitea/gitea/issues/23977
Related: https://github.com/go-gitea/gitea/issues/18703

modules/queue/queue_channel_test.go

@@ -4,6 +4,7 @@
 package queue
 
 import (
+	"os"
 	"sync"
 	"testing"
 	"time"
@@ -101,6 +102,9 @@ func TestChannelQueue_Batch(t *testing.T) {
 }
 
 func TestChannelQueue_Pause(t *testing.T) {
+	if os.Getenv("CI") != "" {
+		t.Skip("Skipping because test is flaky on CI")
+	}
 	lock := sync.Mutex{}
 	var queue Queue
 	var err error