sql: unskip Insights test

This test has been flaky for a while because of the async tagging
of the TransactionID to the insight that somtimes takes too long to
complete. This change removes that check and unskips the test so that
we can catch regressions for this feature. In the future we may want
to write a separate test to verify the async transactionID tagging
separately.

Resolves: cockroachdb#125771
Resolves: cockroachdb#121986

Epic: None
Release note: None

pkg/sql/sqlstats/insights/integration/insights_test.go

@@ -696,8 +696,6 @@ func TestInsightsIntegrationForContention(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 	defer log.Scope(t).Close(t)
 
-	skip.WithIssue(t, 121986)
-
 	// Start the cluster. (One node is sufficient; the outliers system is currently in-memory only.)
 	ctx := context.Background()
 	settings := cluster.MakeTestingClusterSettings()
@@ -766,13 +764,11 @@ func TestInsightsIntegrationForContention(t *testing.T) {
 	// lookup this id will result in the resolver potentially missing the event.
 	txnIDCache := tc.ApplicationLayer(0).SQLServer().(*sql.Server).GetTxnIDCache()
 	txnIDCache.DrainWriteBuffer()
-	var expectedWaitingTxnFingerprintID appstatspb.TransactionFingerprintID
 	testutils.SucceedsSoon(t, func() error {
 		waitingTxnFingerprintID, ok := txnIDCache.Lookup(waitingTxnID)
 		if !ok || waitingTxnFingerprintID == appstatspb.InvalidTransactionFingerprintID {
 			return fmt.Errorf("waiting txn fingerprint not found in cache")
 		}
-		expectedWaitingTxnFingerprintID = waitingTxnFingerprintID
 		return nil
 	})
 
@@ -849,11 +845,6 @@ func TestInsightsIntegrationForContention(t *testing.T) {
 				continue
 			}
 
-			if waitingTxnFingerprintID == "0000000000000000" || waitingTxnFingerprintID == "" {
-				lastErr = fmt.Errorf("expected waitingTxnFingerprintID to be %d, but got %s. \nScanned row: \n%s", expectedWaitingTxnFingerprintID, waitingTxnFingerprintID, prettyPrintRow)
-				continue
-			}
-
 			foundRow = true
 			break
 		}