Enhancement: Allow the user to download the last generated speech response

[rmusser01]

Title.

As a user, I would like the ability to download the last generated speech response via TTS.
Since responses are dynamically generated and may differ from prior and post-generated versions, I would like the ability to download and store individual responses outside of the application.

Resolution of this issue would be to have a button available in the UI that would check to see if an audio file exists for the last chat response, and if it does, provide it as a a download. If the file is not available, it should indicate as such to the user.