Fix LM loading error

Fixes https://demo.arkindex.org/process/13d1c2ad-d7e0-4a6f-9ef5-0f86bccecbeb/0

TypeError: __init__(): incompatible constructor arguments. The following argument types are supported:
    1. torchaudio.flashlight_lib_text_dictionary.Dictionary()
    2. torchaudio.flashlight_lib_text_dictionary.Dictionary(filename: str)
    3. torchaudio.flashlight_lib_text_dictionary.Dictionary(tkns: List[str])
Invoked with: PosixPath('/data/current/tokens.txt')

The CTC loader, only used when the model needs a LM, expects either str or List[str] and doesn't like our PosixPath instances here.

So for now I cast these to str.

changed milestone to %ML Prod - May 2023 n°2

added P1 Quick Win labels

requested review from @starride

assigned to @schneider-y

approved this merge request

merged