PlotlyJS.image incorrectly serializes to json the z array of size (d, rows, cols) , d=3, 4

Example:
```
plt=Plot(image(z=rand(0:255, (3, 6, 4)), colormodel="rgb", x0=1, y0=1),
Layout(width=500, height=335))
```

To get the right image the following `permutedims` of the array of size (d, rows, cols) = (3, 6, 4) must be performed:
```
Plot(image(z=permutedims(rand(0:255, (3, 6, 4)), (1, 3,2)), colormodel="rgb", x0=1, y0=1))
```

Start by running the provided Plot(image(...)) example and compare its output with the permutedims workaround. Trace how the image z array is serialized for a (d, rows, cols) shape, and consider the issue done when the original (3, 6, 4) RGB input produces the correct image without manual permutation.

Written by the indexing model from the issue text.