The channel slider works only for a single channel image.

When adding two images, the channel slider (bottom of the interface) doesn't work on the second image; to fix one needs to first delete the first image.

To reproduce, run the code:

from spatialdata import SpatialData
from spatialdata.models import Image2DModel
from napari_spatialdata import Interactive
from numpy.random import default_rng

RNG = default_rng(0)
image0 = Image2DModel.parse(RNG.random((5, 100, 100)))
image1 = Image2DModel.parse(RNG.random((5, 100, 100)))

sdata = SpatialData.init_from_elements({'image0': image0, 'image1': image1})

Interactive(sdata)

and then:

1. add image0, the slider in the bottom of the interface works
2. add image1 (which is now in focus), the slide will not work
3. delete image0, the slider will work again, on image1.

Start by running the provided Python reproduction with Interactive and two Image2DModel images, then trace how the channel slider handles the focused image when both image0 and image1 are present. Done means the slider changes channels for image1 without requiring image0 to be deleted, while preserving the existing single-image behavior.