getEncounters doesn't sortBy cancelDateTime

[mahalakshme]

Issue:
getEncounters function in Individual.js and ProgramEnrolment.js has facility to consider cancelled encounters as well. But it is not considering cancelDateTime when sorting the encounters. Hence when need to get the latest(including cancelled encounters) another sorting as below need to be done in the report card query:

const encounters = enrolment.getEncounters(false);
      const sortedEncounters = _.sortBy(encounters, (encounter) => {
      return _.isNil(encounter.cancelDateTime)? moment().diff(encounter.encounterDateTime) : 
      moment().diff(encounter.cancelDateTime)}); 
      const latestEncounter = _.head(sortedEncounters);

Significance of fixing this issue:

• To prevent code duplication of above in the implementations
• For faster work in implementation team.