Fix unneccessary use of template keyword

[csparker247]

When attempting to build openMVS on macOS 15.6, I received the following compiler error:

/Users/REDACTED/include/vcg/vcg/complex/algorithms/update/selection.h:109:48: error: a template argument list is expected after a name prefixed by the template keyword [-Wmissing-template-arg-list-after-template-kw]
  109 |     if(! (Allocator<ComputeMeshType>::template IsValidHandle(*_m, vsH))) return false;
      |                                                ^
In file included from /Users/REDACTED/build/openMVS-prefix/src/openMVS/libs/MVS/Mesh.cpp:51:
...

I don't know why this is suddenly an error in Apple Clang, but this removes the unnecessary use of template.

[cdcseacave]

thank you, but this fork is not needed anymore, as the latest official VCG seems fine now