cellsystems images can't be downloaded from Plot view

## Description

The CFE plot deals in single cells but the cellsystems data only provides full FOV tiff images to download. The download links generated by the plot view are trying to use cell ids instead of fov ids. As a result, you can't download anything at all from the Plot view links.

If you try to download from the 3d viewer, it already knows it has a full field image and you can download the image correctly from there. the bug only applies to the download links generated from the Plot view (edited)

## Expected Behavior

When I click a download link I expect images to be downloaded.

## Reproduction

Go to CFE, load one of the cellsystems data sets.
Select a small number of points (ideally even just one ) in the scatterplot.
The download link generated for that selection set shows ids of the form F####C## which is a cell id. But the only images available to download are FOV ids of the form F####.