Fix project settings not being able to update

Previously import_url would always be present in the update parameters,
which would cause the validation to fail. We now only include this
parameter only if there is URL given.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/62708

app/controllers/concerns/import_url_params.rb

@@ -2,6 +2,8 @@
 
 module ImportUrlParams
   def import_url_params
+    return {} unless params.dig(:project, :import_url).present?
+
     { import_url: import_params_to_full_url(params[:project]) }
   end
 

changelogs/unreleased/sh-fix-import-url-update.yml

+---
+title: Fix project settings not being able to update
+merge_request: 29097
+author:
+type: fixed

spec/controllers/concerns/import_url_params_spec.rb

@@ -8,6 +8,18 @@ describe ImportUrlParams do
     controller.import_url_params
   end
 
+  context 'empty URL' do
+    let(:params) do
+      ActionController::Parameters.new(project: {
+        title: 'Test'
+      })
+    end
+
+    it 'returns empty hash' do
+      expect(import_url_params).to eq({})
+    end
+  end
+
   context 'url and password separately provided' do
     let(:params) do
       ActionController::Parameters.new(project: {