Fix clinicaltrials error by adding missing kwargs (#482)
ClinicalTrials.call() raises an error due an unexpected keyword
argument, 'session'. Resolved by adding **kwargs to the call method.
This PR also converts the method to async for consistency with the other
community tools.
Co-authored-by: Luísa Moura <luisa@cohere.com>
Co-authored-by: Tianjing Li <tianjinglimail@gmail.com>
