BTD-378 Parse and Handle Errors from LRS API

[Ewan-Donovan]

The core idea was to handle errors from LRS by parsing them and throwing exceptions:

if (lrsResponse.isSuccessful && lrsResponseBody != null) {
  return convertLrsResponseToOurResponse(findLearnerByDemographicsRequest, lrsResponseBody)
} else {
  throw LRSException(parseError(lrsResponse.errorBody()?.string().toString()))
}

The LRS Exception is handled by the error handler with a new method