Allow empty `VisualizationInfo` XML nodes in .bcfv files

modules/bim/lib/open_project/bim/bcf_json/viewpoint_reader.rb

@@ -28,7 +28,7 @@ module OpenProject::Bim
         @viewpoint_hash ||= begin
           # Load from XML using activesupport
           hash = Hash.from_xml(xml)
-          hash = hash[ROOT_NODE] if hash.key?(ROOT_NODE)
+          hash = hash[ROOT_NODE] if hash[ROOT_NODE]
 
           # Perform destructive transformations
           transformations.each do |method_name|
@@ -58,6 +58,7 @@ module OpenProject::Bim
       def remove_keys(hash)
         hash.delete 'xmlns:xsi'
         hash.delete 'xmlns:xsd'
+        hash.delete 'VisualizationInfo' unless hash['VisualizationInfo']
       end
 
       def set_uuid(hash)

modules/bim/spec/fixtures/viewpoints/empty.bcfv.json

@@ -0,0 +1,3 @@
+{
+  "guid": "{{UUID}}"
+}

modules/bim/spec/fixtures/viewpoints/empty.bcfv.xml

@@ -0,0 +1,2 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<VisualizationInfo />

modules/bim/spec/lib/open_project/bcf/bcf_json/viewpoint_reader_spec.rb

@@ -33,6 +33,14 @@ describe OpenProject::Bim::BcfJson::ViewpointReader do
   let(:instance) { described_class.new xml_viewpoint.uuid, xml_viewpoint.viewpoint }
   subject { instance.result }
 
+  describe 'with empty example' do
+    let_it_be(:xml_viewpoint) do
+      FactoryBot.build_stubbed :xml_viewpoint, viewpoint_name: 'empty.bcfv'
+    end
+
+    it_behaves_like 'matches the JSON counterpart'
+  end
+
   describe 'with minimal example' do
     let_it_be(:xml_viewpoint) do
       FactoryBot.build_stubbed :xml_viewpoint, viewpoint_name: 'minimal.bcfv'