[IMP] utm, mass_mailing: clean utm.campaign model, form view and stat buttons

This commit cleans up the utm.campaign form view:

  * Don't display mailing related things if no mailings on the campaign or
    if the campaigns were not activated in mass_mailing settings;
  * Stat button for the mass mailings was wrong, it was displaying the number
    of mails instead of the number of mailings;
  * Remove unused global click ratio field all other fields/methods related
    to its computation;
  * Remove ab testing cta on campaign form;
  * Add groups on mailing related fields to avoid access errors;

LINKS

Task ID 2074813 (FP request UTM refactor)
PR: #37185

0 files changed, 0 insertions, 0 deletions