[tests] Remove format 138 from tests (#4559)

test/test_YoutubeDL.py

@@ -218,7 +218,7 @@ class TestFormatSelection(unittest.TestCase):
             # 3D
             '85', '84', '102', '83', '101', '82', '100',
             # Dash video
-            '138', '137', '248', '136', '247', '135', '246',
+            '137', '248', '136', '247', '135', '246',
             '245', '244', '134', '243', '133', '242', '160',
             # Dash audio
             '141', '172', '140', '171', '139',