Bounding coordinates set to 0 don't display on dataset landing pages rendered from the index

[robyngit]

The bounding coordinates are not displayed correctly on dataset landing pages that are rendered from the index when coordinates are set to 0. See for example, this dataset which has a southBound coord set to 0. The south coordinate is not shown and the Google Map preview is broken.

I assume the problem occurs because the code incorrectly treats 0 as a falsy value, leading to the coordinates not being shown. We are doing that here for example, and repeating the same check elsewhere.

Seems like we could use a function like:

const allCoordsExist = () => {
  const coordAttrs = ["northBoundCoord", "eastBoundCoord", "southBoundCoord", "westBoundCoord"];
  return coordAttrs.every(attr => model.get(attr) !== undefined);
}