[Bug] Check "skip obs that error" fix ported to Vizarr

[davehorsfall]

Describe the bug
Daniela noted bug in biongff-viewer that impacted the Anndata-zarr plugin. A fix was provided in biongff-viewer PR#44

Need to ensure this fix has been ported to TypeScript implementation in Vizarr.

[AlexSurtees]

1. Ensure that while loading the observation and feature names from zarr arrays, any errors just prevent that label from loading in the UI, rather than crashing the whole app/plugin.
2. Ensure that when the user clicks a feature/observation, any errors occurring from loading the zarr array data and creating the colourMap are handled gracefully.
3. Mock test data can easily be produced, hosted, and included in the fixtures to test these cases.