[cmake] Build xdmf libs only when OGS_BUILD_TESTING=ON.

scripts/cmake/Dependencies.cmake

@@ -403,7 +403,7 @@ if(OGS_USE_PETSC)
     endif()
 endif()
 
-if((OGS_BUILD_TESTING OR OGS_BUILD_UTILS) AND NOT GUIX_BUILD)
+if(OGS_BUILD_TESTING AND NOT GUIX_BUILD)
     set(XDMF_LIBNAME OgsXdmf CACHE STRING "")
     CPMAddPackage(
         NAME xdmf