Add time.Sleep() in TestUpdateTableIndexMetrics to avoid flakiness in CI

Signed-off-by: Florent Poinsard <florent.poinsard@outlook.fr>

Author: frouioui

go/vt/vttablet/endtoend/misc_test.go

@@ -1112,6 +1112,8 @@ func TestUpdateTableIndexMetrics(t *testing.T) {
 		require.NoError(t, err)
 	}
 
+	time.Sleep(5 * time.Second)
+
 	err = framework.Server.ReloadSchema(ctx)
 	require.NoError(t, err)
 
@@ -1120,6 +1122,8 @@ func TestUpdateTableIndexMetrics(t *testing.T) {
 	pageSize, err := results.Rows[0][0].ToFloat64()
 	require.NoError(t, err)
 
+	time.Sleep(5 * time.Second)
+
 	vars := framework.DebugVars()
 
 	assert.Equal(t, 2.0, framework.FetchVal(vars, "TableRows/vitess_a"))