tf2centerprojectiles gamedata update

[rtldg]

I don't know exactly which update changed the offset for IsViewModelFlipped (or when), but the vtable dumper shows different ones, so I made a commit to match (rtldg/tf2centerprojectiles@2703945 (main branch)).

I also don't know how the plugin-updating / submodule system works in the repo, so I'm making an issue rather than a PR.

Thanks for continuing to use the plugin btw :)))