[Error] when uploading txt file to source materials bucket

Revieve following error from the read-source-and-build-index Lambda function when I try to upload attached .txt file to the source materials bucket. Able to execute with a pdf instead
[allergies_faq.txt](https://github.com/aws-samples/aws-lex-conv-faq/files/13221499/allergies_faq.txt)
```
[ERROR] TypeError: __init__() takes 1 positional argument but 2 were givenTraceback (most recent call last):  File "/var/task/index_creation_app.py", line 63, in handler    documents = [Document(t) for t in text_list]  File "/var/task/index_creation_app.py", line 63, in     documents = [Document(t) for t in text_list] | [ERROR] TypeError: __init__() takes 1 positional argument but 2 were given Traceback (most recent call last):   File "/var/task/index_creation_app.py", line 63, in handler     documents = [Document(t) for t in text_list]   File "/var/task/index_creation_app.py", line 63, in     documents = [Document(t) for t in text_list]
-- | --
```

Start in index_creation_app.py at line 63, where text_list is converted into Document objects in the read-source-and-build-index Lambda function. Reproduce the upload with allergies_faq.txt and compare it with the working PDF path. Done means a .txt upload completes without the reported TypeError and builds the index successfully.

Written by the indexing model from the issue text.