Use merge request organisations association instead of field

app/helpers/merge_requests_helper.rb

@@ -14,7 +14,7 @@ module MergeRequestsHelper
   def merge_details(merge_request)
     [
       { label: "Absorbing organisation", value: display_value_or_placeholder(merge_request.absorbing_organisation_name), action: merge_request.status == "request_merged" ? nil : { text: "Change", href: absorbing_organisation_merge_request_path(merge_request), visually_hidden_text: "absorbing organisation" } },
-      { label: "Merging organisations", value: merge_request.other_merging_organisations.present? ? merge_request.other_merging_organisations.split(",").map(&:strip).join("<br>").html_safe : display_value_or_placeholder(nil), action: merge_request.status == "request_merged" ? nil : { text: "Change", href: organisations_merge_request_path(merge_request), visually_hidden_text: "merging organisations" } },
+      { label: "Merging organisations", value: merge_request.merge_request_organisations.any? ? merge_request.merge_request_organisations.map(&:merging_organisation_name).join("<br>").html_safe : display_value_or_placeholder(nil), action: merge_request.status == "request_merged" ? nil : { text: "Change", href: organisations_merge_request_path(merge_request), visually_hidden_text: "merging organisations" } },
       { label: "Merge date", value: display_value_or_placeholder(merge_request.merge_date), action: merge_request.status == "request_merged" ? nil : { text: "Change", href: merge_date_merge_request_path(merge_request), visually_hidden_text: "merge date" } },
     ]
   end

app/models/merge_request_organisation.rb

@@ -10,6 +10,10 @@ class MergeRequestOrganisation < ApplicationRecord
 
   has_paper_trail
 
+  def merging_organisation_name
+    merging_organisation.name || ""
+  end
+
 private
 
   def validate_merging_organisations