feat: --only now applies to package dependencies (#8163)
### Description
Change `--only` so it behaves in a more sensible way. It still shouldn't
be widely used, but now it at least does what it says it does.
Previously `--only` would still follow package dependencies resulting
additional tasks getting run that weren't expected.
e.g. for task definition `"test": {"dependsOn": ["build", "^test"]}` and
package `a` depending on `b`, then `turbo test --filter=a --only` would
result in both `a#test` and `b#test` being run. With this PR now only
`a#test` will be run.
I changed the `--only` logic so now it will limit tasks in the graph to
exactly those that are in the product of the packages implied by
`--filter` and the tasks specified in the run args. This should make
`--only` a far more sensible flag.
### Testing Instructions
Added unit tests for testing the trimming of package dependencies and
task id style dependencies e.g. `"dependsOn": ["a#test"]`
