update webdriver test (#4829)

fix a webdriver test that broke with new population data. 

Update the check to just look for values along the y axis instead of
checking the actual value which can change

server/webdriver/shared_tests/ranking_test.py

@@ -112,5 +112,5 @@ def test_population_top_ranking_ko(self):
     chart = self.driver.find_element(By.CLASS_NAME, 'chart-container')
     y_text = chart.find_elements(By.CLASS_NAME,
                                  'y')[0].find_elements(By.TAG_NAME, 'text')
+    self.assertGreater(len(y_text), 1)
     self.assertEqual(y_text[0].text, '0')
-    self.assertEqual(y_text[-1].text, '12억')