Fixes compilation warnings and errors from gcc-12.3

• Fixes to compilation warnings in gcc-12.3 (also applied to v1-patches branch by commit 7768c71c, see MR #1047.

• Fix TestBVHNavigator compilation warning:

[555/570] Building CXX object test/gdml/CMakeFiles/TestBVHNavigator.dir/TestBVHNavigator/TestBVHNavigator.cpp.o
/work1/celeritas/lima/work/vecgeom/test/gdml/TestBVHNavigator/TestBVHNavigator.cpp: In function ‘int main(int, char**)’:
/work1/celeritas/lima/work/vecgeom/test/gdml/TestBVHNavigator/TestBVHNavigator.cpp:159:13: warning: pointer used after ‘void operator delete(void*, std::size_t)’ [-Wuse-after-free]
  159 |     navigate(p, dir, navigator, ref_navigator);
      |     ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/work1/celeritas/lima/work/vecgeom/test/gdml/TestBVHNavigator/TestBVHNavigator.cpp:156:12: note: call to ‘void operator delete(void*, std::size_t)’ here
  156 |     delete navigator;
      |            ^~~~~~~~~