fix remove organisation

app/controllers/merge_requests_controller.rb

@@ -36,7 +36,7 @@ class MergeRequestsController < ApplicationController
   end
 
   def remove_merging_organisation
-    MergeRequestOrganisation.find_by(merge_request_organisation_params).destroy!
+    MergeRequestOrganisation.find_by(merge_request_organisation_params)&.destroy!
     @merge_request.reload
     @answer_options = organisations_answer_options
     @merging_organisations_list = [@merge_request.requesting_organisation] + @merge_request.merging_organisations

app/views/merge_requests/organisations.html.erb

@@ -38,7 +38,7 @@
             scope: "row",
             class: "govuk-!-text-align-right",
           }) do %>
-            <%= govuk_link_to("Remove", merge_request_organisations_path) %>
+            <%= govuk_link_to("Remove", merge_request_organisations_remove_path(merge_request: { merging_organisation: merging_organisation.id })) %>
           <% end %>
         <% end %>
       <% end %>

spec/requests/merge_requests_controller_spec.rb

@@ -140,7 +140,7 @@ RSpec.describe MergeRequestsController, type: :request do
     describe "#remove_organisation" do
       let(:params) { { merge_request: { merging_organisation: other_organisation.id } } }
 
-      context "when removing an organisation from merge request " do
+      context "when removing an organisation from merge request" do
         before do
           MergeRequestOrganisation.create!(merge_request_id: merge_request.id, merging_organisation_id: other_organisation.id)
           get "/merge-request/#{merge_request.id}/organisations/remove", headers:, params:
@@ -151,6 +151,17 @@ RSpec.describe MergeRequestsController, type: :request do
           expect(page).not_to have_link("Remove")
         end
       end
+
+      context "when removing an organisation that is not part of a merge from merge request" do
+        before do
+          get "/merge-request/#{merge_request.id}/organisations/remove", headers:, params:
+        end
+
+        it "does not throw an error" do
+          expect(merge_request.merging_organisations.count).to eq(0)
+          expect(page).not_to have_link("Remove")
+        end
+      end
     end
 
     describe "#other_merging_organisations" do