fix: typo in test (langgenius#10707)

Signed-off-by: yihong0618 <zouzou0208@gmail.com>

api/tests/unit_tests/core/workflow/nodes/test_document_extractor_node.py

@@ -140,10 +140,10 @@ def test_extract_text_from_plain_text():
     assert text == "Hello, world!"
 
 
-def tet_extract_text_from_plain_text_non_utf8():
+def test_extract_text_from_plain_text_non_utf8():
     import tempfile
 
-    non_utf8_content = b"Hello world\xa9."  # \xA9 represents © in Latin-1
+    non_utf8_content = b"Hello, world\xa9."  # \xA9 represents © in Latin-1
     with tempfile.NamedTemporaryFile(delete=True) as temp_file:
         temp_file.write(non_utf8_content)
         temp_file.seek(0)