Incorrect .ovr file detection with presigned URLs

I've encountered an issue while using [STAC Browser](https://radiantearth.github.io/stac-browser). The method for discovering `.ovr` files is quite [simplistic](https://github.com/GeoTIFF/georaster/blob/686ba4ead8205104cac4a966b45d14615d64520a/src/index.js#L99) and fails when dealing with presigned URLs. As a result, `georaster` generates URLs like this:

```
https://.../analytic.tiff?X-Amz-Signature=db052c40c08fcff9c36746421df18c9a2554b43589d231ebc07e8ae930deaf28.ovr
```

This appends `.ovr` to the signature, which obviously doesn't work. I believe `.ovr` detection should be disabled for presigned URLs, as each file has a unique signature, making it impossible to access the `.ovr` file using the `.tiff` file's signature.