added message secure check in subscribe_block
message secure doesnt have to be set in case plugin gets updated in older projects and views were overwritten
Added check if message_secure is set during unsubscribe to prevent spambot breakage for older projects
Added listSentCampaigns method in CampaignMonitor library. refs #15660
strip tags and decode html entities from email subjects (if they get translated in the static string module)
Added ENT_COMPAT flag + encoding parameter to html_entity_decode email subjects.