chore: Handle unsupported geometries (e.g. point empty) in GeoExecutor

In multiple PRs implementing `geo` kernels (e.g. [1](https://github.com/apache/sedona-db/pull/469) and [2](https://github.com/apache/sedona-db/pull/233)), we've run across the [item_to_geometry()](https://github.com/apache/sedona-db/blob/e0e1d109480727faaf7be25923b57b4686144438/rust/sedona-geo/src/to_geo.rs#L62-L66) lack of support for certain geometries like point empty. The root of the problem is that `geo`'s methods simply return `None` for many of those cases.

In https://github.com/apache/sedona-db/pull/233#discussion_r2619908849, @paleolimbot proposed creating a new enum to allow the caller to access the WKB directly.

```rust
enum ItemToGeometryResult { Unsupported(Wkb), Supported(Geometry))
```

I thought about taking this one step further, what if we instead do something like this:

```rust
enum ItemToGeometryResult {
PointEmpty,
MultiPointEmpty, // we'd have to be extra careful here for cases like `MULTIPOINT (EMPTY, 1 0)`
Supported(Geometry),
Unsupported(Wkb), // or just continue allowing these cases to panic since these are complicated cases anyway
}
```

This would allow us to avoid re-parsing the Unsupported geom's bytes again to determine that it's an empty point/polygon. This should work because we *know* what method is returning the `None` inside of the following function

https://github.com/apache/sedona-db/blob/e0e1d109480727faaf7be25923b57b4686144438/rust/sedona-geo/src/to_geo.rs#L76-L87

Start with rust/sedona-geo/src/to_geo.rs, especially item_to_geometry(), then inspect its GeoExecutor callers and the referenced PR discussions. Determine how empty points, empty multipoints, and other unsupported geometries should be represented without losing access to the original WKB. Done means the chosen behavior is implemented and the affected geo kernels handle these cases consistently.

Written by the indexing model from the issue text.