STYLE: Make conversion from value to itk::Point or itk::Vector explicit

Allowing ITK_LEGACY_REMOVE=0N for ITK version >= 5.3rc04, which made those constructors `explicit`:

 - ITK pull request InsightSoftwareConsortium/ITK#3237 commit InsightSoftwareConsortium/ITK@8825834 "ENH: Declare converting `Point(v)` constructors `explicit`"
 - ITK pull request InsightSoftwareConsortium/ITK#3255 commit InsightSoftwareConsortium/ITK@abb88cc "ENH: Make Vector constructor from scalar explicit, unless LEGACY enabled"

Common/GTesting/elxTransformIOGTest.cxx

@@ -308,8 +308,8 @@ struct WithDimension
 
       const auto imageContainer = elx::ElastixBase::DataObjectContainerType::New();
       const auto image = itk::Image<float, NDimension>::New();
-      image->SetOrigin(testValue);
-      image->SetSpacing(testValue);
+      image->SetOrigin(itk::Point<double, NDimension>(testValue));
+      image->SetSpacing(itk::Vector<double, NDimension>(testValue));
       imageContainer->push_back(image);
 
       elastixObject->SetFixedImageContainer(imageContainer);