[SIGMON-658] No notebooks content checks

Context

• issue: https://its.cern.ch/jira/browse/SIGMON-658
• job is green: https://gitlab.cern.ch/LHCData/lhc-sm-hwc/-/jobs/37798745

What was done

• test_notebooks.py updated so that the content of the executed notebook is not checked
• reference .html and .ipyn files removed
• notebooks_exec_requirements.txt updated to the new Software Stack on SWAN
• queries in PGC2 updated to reflect the change in the column names returned from the queries (removing the entity queries)

Closes SIGMON-658