Confirm that the conda package uses installed `spglib` C library

- [x] If we delete `site-packages/spglib/libsymspg*` does it still work? Yes
- [x] ~~If we install a local spglib library, is it picked up?~~ (One way to test is to install one with different version defined and call `spglib.get_version()`.) No, only the conda version seems to be picked up
- [x] If we delete `lib/libsymspg*` does it default to locally installed? No