git: Refactor pack-objects hook configuration
This is a small refactoring MR the recently-added pack-objects hook configuration:
- The git binary path is now injected via the HooksPayload.
- We use
configureHooks()
, which buys us protection from overriding the payload by accident. - I've added additional testcases to verify the pack-objects hook configuration works as expected.
- The
uploadpack.packObjectsHook
is now injected inWithPackObjectsHookEnv()
.