Remove the duplicate hidden namespace_id field on the import page

app/views/import/gitlab_projects/new.html.haml

@@ -14,7 +14,6 @@
       = _("To move or copy an entire GitLab project from another GitLab installation to this one, navigate to the original project's settings page, generate an export file, and upload it here.")
   .row
     .form-group.col-sm-12
-      = hidden_field_tag :namespace_id, @namespace.id
       = label_tag :file, _('GitLab project export'), class: 'label-bold'
       .form-group
         = file_field_tag :file, class: ''

changelogs/unreleased/24804-import-page-namespace-fix.yml

+---
+title: Fixed project import from export ignoring namespace selection
+merge_request: 20405
+author:
+type: fixed

spec/views/import/gitlab_projects/new.html.haml_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'import/gitlab_projects/new.html.haml' do
+  include Devise::Test::ControllerHelpers
+
+  let(:user) { build_stubbed(:user, namespace: build_stubbed(:namespace)) }
+
+  before do
+    allow(view).to receive(:current_user).and_return(user)
+  end
+
+  context 'when the user has no other namespaces' do
+    it 'shows a namespace_id hidden field tag' do
+      render
+
+      expect(rendered).to have_css('input[name="namespace_id"]', count: 1, visible: false)
+    end
+  end
+
+  context 'when the user can select other namespaces' do
+    it 'shows a namespace_id select' do
+      allow(user).to receive(:can_select_namespace?).and_return(true)
+
+      render
+
+      expect(rendered).to have_select('namespace_id', count: 1)
+    end
+  end
+end