Participant role is no longer displayed in custom event name badges

When generating custom name badge templates, as described in the documentation, the participant role (as text name) was previously available to the generateLabel function (overridden from the CRM_Event_Badge class) via the $participant['participant_role'] variable. This has been discarded (without warning) in version 3.3.x, presumably in relation to CRM-6507, which added multiple participant roles.

Whilst it is possible to work around this, using $participant['participant_role_id'] and looking up the text equivalent with CRM_Event_PseudoConstant::participantRole(), this only works when only one role is selected. For some reason, if multiple roles are selected for the participant, the $participant['participant_role_id'] variable contains a concatenated list of ids, rather than an array, making it entirely useless. For example, if the participant is a Volunteer and a Speaker, they will have $participant['participant_role_id'] returned as 24. I guess this is fine until you have more than 9 participant roles (which we do).