Update looking glass reports name to be more unique

Currently in the looking glass tests workflow, the report filename only uses the current commit and the new commit along with the test type (pandas, dask, spark) in setting the filename. This means that if multiple runs are launched comparing the same two commits, the previous report will be overwritten. We should update the naming to perhaps also include a timestamp so that each run will be unique and we won't unintentionally overwrite previous results.