Move git.DiffPath to gitserver.Client
Created by: vrto
Description
This change is a part of a larger effort to reorganize code in gitserver. The Repository Management Team is moving git commands from internal/vcs/git
to internal/gitserver
.
See this issue for more details https://github.com/sourcegraph/sourcegraph/issues/33280
Closes https://github.com/sourcegraph/sourcegraph/issues/33439
Test plan
Code only moved around, all tests still pass.