[llvm-objdump] Change printSymbolVersionDependency to use ELFFile API

When .gnu.version_r is empty (allowed by readelf but warned by objdump),
llvm-objdump -p may decode the next section as .gnu.version_r and may crash due
to out-of-bounds C string reference. ELFFile<ELFT>::getVersionDependencies
handles 0-entry .gnu.version_r gracefully. Just use it.

Fix https://github.com/llvm/llvm-project/issues/57707

Differential Revision: https://reviews.llvm.org/D133751