fix(UnpaywallImportService): prevent exception blocking the deposit process...

if (bronze && has_repository_copy) {
  if(some location with license exists) {
      we take the 1st one:
        - accessLevel -> public
        - license -> "Other OA"
        - url_for_pdf
        - version
  
    } else {
      we take the 1st one without license:
        - accessLevel -> restricted
        - license -> null
        - url_for_pdf
        - version
    }  
} elseif ("best_oa_location" exists) {
  we take from "best_oa_location":
    - accessLevel -> restricted
    - url_for_pdf
    - license:
      - if the name is known in AoU, we use it
      - if there is a name, but it is unknown in AoU --> « Other OA »
      - if null -> null
    - version
} else {
  we don't take anything
}