Enable filtering in galactic coordinates

Enable the user to specify the filtering regions (e.g., [box](https://github.com/astronomy-commons/lsdb/blob/25cf48b318e1a09983d26364f11b6b15f3a1ac47/src/lsdb/catalog/catalog.py#L206)), in galactic coordinates.

Possibly API might be (do they use ra/dec for galactic?):

`Catalog.box(ra=(340, 342), dec=(340, 342)), coordinates = 'galactic')`

The initial suggestion is to have the galactic coordinates box/region transformed into polygon in Equatorial Coordinate System that is sampled with a ``sufficent'' density. From there use existing functionality.

In case that this turns out to be problematic, report back to consider alternative approaches (via e.g., astropy regions).

Connected with https://github.com/astronomy-commons/hipscat/issues/152

**Before submitting**
Please check the following:

- [X] I have described the purpose of the suggested change, specifying what I need the enhancement to accomplish, i.e. what problem it solves.
- [X] I have included any relevant links, screenshots, environment information, and data relevant to implementing the requested feature, as well as pseudocode for how I want to access the new functionality.
- [X] If I have ideas for how the new feature could be implemented, I have provided explanations and/or pseudocode and/or task lists for the steps.

Start by reading the existing Catalog.box implementation in src/lsdb/catalog/catalog.py and the linked hipscat issue. Determine how galactic coordinate regions should map onto the current equatorial filtering path, including the unresolved API and sampling concerns. Done means users can request galactic-coordinate regions while existing filtering behavior remains correct.

Written by the indexing model from the issue text.