Clean up get_audio try/catch

The prior implementation made a best effort to continue in the event of
an error, but immediately threw an error afterwards since there was no
output from the subprocess.

As get_audio isn't called until the audio connection from a Load Video
is used, it's safe to raise an exception here and properly expose the
error message from ffmpeg as is done elsewhere.

See Kosinkadink#250

videohelpersuite/utils.py

@@ -166,10 +166,10 @@ def get_audio(file, start_time=0, duration=0):
         res =  subprocess.run(args + ["-f", "f32le", "-"],
                               capture_output=True, check=True)
         audio = torch.frombuffer(bytearray(res.stdout), dtype=torch.float32)
+        match = re.search(', (\\d+) Hz, (\\w+), ',res.stderr.decode('utf-8'))
     except subprocess.CalledProcessError as e:
-        logger.warning(f"Failed to extract audio from: {file}")
-        audio = torch.zeros(1,2)
-    match = re.search(', (\\d+) Hz, (\\w+), ',res.stderr.decode('utf-8'))
+        raise Exception(f"VHS failed to extract audio from {file}:\n" \
+                + e.stderr.decode("utf-8"))
     if match:
         ar = int(match.group(1))
         #NOTE: Just throwing an error for other channel types right now