STYLE: Remove unused joinElements and clean up VoxBoCUB test temp file

Remove the now-unused joinElements helper from itkMetaImageIO.cxx,
as its only call site was replaced with a ConvertNumberToString loop.

Add temp file cleanup in the VoxBoCUB precision sub-test.

Addresses review comments from @N-Dekker and @greptile-apps on PR #6003.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hjmjohnson

Modules/IO/Meta/src/itkMetaImageIO.cxx

@@ -28,21 +28,6 @@
 
 #include <set>
 
-// Function to join strings with a delimiter similar to python's ' '.join([1, 2, 3 ])
-template <typename ContainerType, typename DelimiterType, typename StreamType>
-static auto
-joinElements(const ContainerType & elements, const DelimiterType & delimiter, StreamType & strs) -> void
-{
-  for (size_t i = 0; i < elements.size(); ++i)
-  {
-    strs << elements[i];
-    if (i != elements.size() - 1)
-    {
-      strs << delimiter;
-    }
-  }
-}
-
 namespace itk
 {
 // Explicitly set std::numeric_limits<double>::max_digits10 this will provide

Modules/Nonunit/Review/test/itkVoxBoCUBImageIOTest.cxx

@@ -23,6 +23,7 @@
 #include "itkVoxBoCUBImageIO.h"
 #include "itkNumberToString.h"
 #include "itkTestingMacros.h"
+#include "itksys/SystemTools.hxx"
 
 int
 itkVoxBoCUBImageIOTest(int argc, char * argv[])
@@ -92,6 +93,7 @@ itkVoxBoCUBImageIOTest(int argc, char * argv[])
     ITK_TRY_EXPECT_NO_EXCEPTION(precReader->Update());
 
     const double readSpacing = precReader->GetOutput()->GetSpacing()[0];
+    itksys::SystemTools::RemoveFile(precFname);
     if (readSpacing != hpSpacing)
     {
       std::cerr << "VoxBoCUB spacing precision loss: wrote " << itk::ConvertNumberToString(hpSpacing)