[CLAP] Support batched inputs for CLAP. Fixes pipeline issues
# What does this PR do?
Support batching the `is_longer` part of the input for `zero_shot_audio_classification`. The model was not able to run batched inputs. Added a test to support this. 
_The documentation is not available anymore as the PR was closed or merged._<|||||>Just need to update the expected values for the doctest and will merge<|||||>Pipeline, CI and doctests are all green 😉 