Hotfix chunk_length_s instead of _ms. (#15029)

* Hotfix `chunk_length_s` instead of `_ms`.

* Adding fix of `pad_token` which should be last/previous token for CTC

proper decoding

* Fixing ChunkPipeline unwrapping.

* Adding a PackIterator specific test.

tests/test_pipelines_common.py

@@ -584,3 +584,14 @@ class PipelineUtilsTest(unittest.TestCase):
 
         outputs = [item for item in dataset]
         self.assertEqual(outputs, [[{"id": 2}, {"id": 3}], [{"id": 4}, {"id": 5}]])
+
+        # is_false Across batch
+        dummy_dataset = [{"id": [0, 1, 2], "is_last": [False, False, False]}, {"id": [3], "is_last": [True]}]
+
+        def add(number, extra=0):
+            return {"id": [i + extra for i in number["id"]], "is_last": number["is_last"]}
+
+        dataset = PipelinePackIterator(dummy_dataset, add, {"extra": 2}, loader_batch_size=3)
+
+        outputs = [item for item in dataset]
+        self.assertEqual(outputs, [[{"id": 2}, {"id": 3}, {"id": 4}, {"id": 5}]])