remove rust-shed from fb303 manifest
remove rust-shed from fb303 manifest

Summary: fb303 contains rust thrift build, but it doesn't run it from its cmake CI, so we can remove this dependency providing that its rust using consumers have the dependency

Reviewed By: Imxset21, fanzeyi

Differential Revision: D33091506

fbshipit-source-id: fc738602104249b5de6c656d59b2eb82987bf1a0

facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst