Fix: Raise an Error for Wrong Input or Output File Formats in Artbox

[investor-uyah]

I was trying an Artbox speech from-text entry and wrongly used --output-path /tmp/artbox/speech.md instead of ...speech.mp3. The code ran successfully. It did not return an error on the wrong output path format. However, I couldn't complete the second part of the exercise that tries to convert speech to text since the output path was invalid.

My suggestion then is to fix the project to detect the input or output file format used and return an error if it is invalid. This could save the user some of their time.