Verify pyharp works with Gradio 6.17.3

[saumya-pailwan]

Local testing

setup.py pins gradio==5.28.0. Before loosening this pin, we should make sure pyharp still works correctly with Gradio 6.17.3.

Things to check

• Small test app: Build a simple app the same way the examples do, and check that all three things HARP needs from a Space still work: reading the app's inputs/outputs, running the main task, and cancelling it.

• Error messages (Example):

  • Gradio's own input checks
  • App's code

• Space test: Run the actual demucs stem-separation Space locally with Gradio 6.17.3:

  • Confirm its inputs/outputs.
  • Mono audio errors.
  • Non errror cases.

Expected result

Nothing should break going from 5.28.0 to 6.17.3, and the main benefit, real error messages reaching the user should work.