The `orchestrate` job maps changed directories to root-workspace package
names, and when no mapping was found it fell back to using the raw
directory name as a package. Because `tooling/lints` is a separate
workspace (not a root-workspace member), a change under
`tooling/lints/**` produced the filter `rdeps(lints)`, which `cargo
nextest run --workspace` rejects with "operator didn't match any
packages" — failing `run_tests` for any such PR. This drops that
fallback so an unmapped directory falls through to the existing "no
package changes → run all tests" path instead.

Release Notes:

- N/A