(maint) Fix ../report_ttl.rb PE Test

Prior to this commit, db_garbage_collection/report_ttl.rb did not pass
on Puppet Enterprise. This commit fixes that in a couple different ways.
First the with_puppet_running_on function had to be changed to master
instead of main. This is so the reports functionality is correctly set
to 'store,puppetdb'. If it was 'main' like the other ones, it would not
set correctly and the reports returned empty. Next, the paths in this
file had to be set dynamically for PE against open source. Finally,
there was an issue with my local version of PE 3 that had to be manually
changed through the command line. This issue was fixed in a newer
install of PE3.