Move Product Intelligence Dangerfile logic to `tooling/danger/product_intelligence.rb`

The following discussion from !75949 (merged) should be addressed:

• @rpereira2 started a discussion: (+1 comment)

  Since we can't test the Dangerfile, it would be useful to move as much logic as possible out of this file and into tooling/danger/product_intelligence.rb, for example like danger/changelog/Dangerfile.

  Should we open a follow-up issue for this?