Error in resample_array() with stereo files

[fegue]

birdnet.utils.resample_array() throws an assertion error assert len(x.shape) == 1 when trying to predict using an audio file in stereo.

I suggest the function should either:

• issue a warning along the lines: Please resample to mono
• Automatically choose a channel
• Implement an argument in predict_species_within_audio_file that lets the user specify a channel.

I tested the behavior with audio files in WAV and FLAC formats, both stereo and mono, at 48kHz and other sample rates across all configurations.

birdnetversion 0.1.6