ci: remove the duplicate pull_request types key that invalidated the inventory harvester workflows

Commit 7f993d7de8 added a types key to the pull_request trigger of the two
inventory harvester workflows, which already declared one behind a comment
line. GitHub rejects mappings with duplicate keys, so both workflow files
have been invalid since then: every push run fails at startup with the
file path as the run name and no jobs, and the workflows never run on pull
requests. Plain YAML parsers accept the duplicate (last key wins), which
is why the mistake survived local validation.