dev/release: rust post-release script requires manual intervention

### What happened?

The Rust Snowflake bindings default to the "bundled" option which expects to be able to find `go/adbc/pkg` at a fixed path. This falls down in `cargo publish` when `cargo` puts a copy of the sources somewhere else. I had to `ln -s` in the directory so it would build. IMO, this should be driven by an env var and the release script should set the env var appropriately so `cargo publish` passes.

### Stack Trace

```
error: failed to run custom build command for `adbc_snowflake v0.18.0 (/Users/lidavidm/Code/arrow-adbc/rust/target/package/adbc_snowflake-0.18.0)`

Caused by:
process didn't exit successfully: `/Users/lidavidm/Code/arrow-adbc/rust/target/package/adbc_snowflake-0.18.0/target/debug/build/adbc_snowflake-d33ba6499356a902/build-script-build` (exit status: 1)
--- stderr
Error: Os { code: 2, kind: NotFound, message: "No such file or directory" }
warning: build failed, waiting for other jobs to finish...
error: failed to verify package tarball
```

### How can we reproduce the bug?

_No response_

### Environment/Setup

_No response_