Fix with_discarded bug in Imms API search job

This was causing the job to create new discarded records every time the
search ran, instead of updating the existing discarded records.

Jira-Issue: MAV-5903

Author: alistair-white-horne-tng

app/jobs/search_vaccination_records_in_nhs_job.rb

@@ -104,6 +104,7 @@ def existing_vaccination_records
     @existing_vaccination_records ||=
       patient
         .vaccination_records
+        .with_discarded
         .includes(:identity_check)
         .sourced_from_nhs_immunisations_api
         .for_programmes(programmes)