Add better image assertions to tool tests when we update to Galaxy v24

[CameronFRWatson]

The latest Galaxy version comes with some nice assertions for imaging data: https://docs.galaxyproject.org/en/latest/dev/schema.html#assertions-for-image-data

When we update our instances/CI to Galaxy >= 24.1, we should implement these assertions in our tools that have image outputs

[CameronFRWatson]

Tools that will likely benefit from the new assertions:

• [ ] ashlar
• [ ] backsub
• [ ] basic-illumination
• [ ] coreograph
• [ ] mti-utils/rename_tiff_channels
• [ ] palom
• [ ] Squidpy (for plot outputs?)