Fix flaky integrations tests (#47217)

In these tests, the events and error channels are closed at
approximately the same time. If the test's select statement
sees the closure of the error channel first, then it will see
a nil error. This should not be considered a test failure, as
there was no error.

integrations/event-handler/teleport_events_watcher_test.go

@@ -190,7 +190,7 @@ func TestEvents(t *testing.T) {
 				return
 			}
 		case err := <-chErr:
-			t.Fatalf("Received unexpected error from error channel: %v", err)
+			require.NoError(t, err)
 			return
 		case <-time.After(2 * time.Second):
 			t.Fatalf("No events received within deadline")
@@ -313,7 +313,7 @@ func TestUpdatePage(t *testing.T) {
 				return
 			}
 		case err := <-chErr:
-			t.Fatalf("Received unexpected error from error channel: %v", err)
+			require.NoError(t, err)
 			return
 		case <-time.After(2 * time.Second):
 			t.Fatalf("No events received within deadline")
@@ -340,7 +340,7 @@ func TestUpdatePage(t *testing.T) {
 				return
 			}
 		case err := <-chErr:
-			t.Fatalf("Received unexpected error from error channel: %v", err)
+			require.NoError(t, err)
 			return
 		case <-time.After(2 * time.Second):
 			t.Fatalf("No events received within deadline")
@@ -367,7 +367,7 @@ func TestUpdatePage(t *testing.T) {
 				return
 			}
 		case err := <-chErr:
-			t.Fatalf("Received unexpected error from error channel: %v", err)
+			require.NoError(t, err)
 			return
 		case <-time.After(2 * time.Second):
 			t.Fatalf("No events received within deadline")
@@ -591,7 +591,7 @@ func TestEventsWithWindowSkip(t *testing.T) {
 				return
 			}
 		case err := <-chErr:
-			t.Fatalf("Received unexpected error from error channel: %v", err)
+			require.NoError(t, err)
 			return
 		case <-time.After(2 * time.Second):
 			t.Fatalf("No events received within deadline")
@@ -607,7 +607,7 @@ func TestEventsWithWindowSkip(t *testing.T) {
 				return
 			}
 		case err := <-chErr:
-			t.Fatalf("Received unexpected error from error channel: %v", err)
+			require.NoError(t, err)
 			return
 		case <-time.After(2 * time.Second):
 			t.Fatalf("No events received within deadline")