Remove uses of business_proposition boolean
Remove uses of business_proposition boolean

This was used for reporting to Google Analytics but that was stopped when we
migrated to Universal Analytics a while ago.

alphagov/publisher,telekomatrix/publisher,leftees/publisher,leftees/publisher,telekomatrix/publisher,telekomatrix/publisher,alphagov/publisher,telekomatrix/publisher,leftees/publisher,alphagov/publisher,leftees/publisher