CLDC-4340: Account for nil location name on location select

use postcode as a fallback, which should never be nil

app/models/form/lettings/questions/location_id.rb

@@ -31,8 +31,9 @@ class Form::Lettings::Questions::LocationId < ::Form::Question
     scheme_location_ids = lettings_log.scheme.locations.visible.confirmed.pluck(:id)
     answer_options.select { |k, _v| scheme_location_ids.include?(k.to_i) }
                   .sort_by { |_, v|
-                    name = v["hint"].match(/[a-zA-Z].*/).to_s
-                    number = v["hint"].match(/\d+/).to_s.to_i
+                    name_or_postcode = v["hint"] || v["value"] # name can be nil, postcode is never nil
+                    name = name_or_postcode.match(/[a-zA-Z].*/).to_s
+                    number = name_or_postcode.match(/\d+/).to_s.to_i
                     [name, number]
                   }.to_h
   end