Changes to Issue one supervision sales invoice for selected meetings

added the optional property updated/items/supervision_deduction_summary/anyOf[subschema #1: SupervisionDeductionSummary]/backlog_count to the response with the 200 status

added the optional property updated/items/supervision_deduction_summary/anyOf[subschema #1: SupervisionDeductionSummary]/withheld_meeting_dates to the response with the 200 status

added the optional property updated/items/expected_invoice_total to the response with the 200 status

added the optional property updated/items/supervision_deduction_summary to the response with the 200 status

endpoint added