text: Title: Unexpected Output Channel Reduction in skimage.transform.rescale without Explicit channel_axis
  Body: ### Description:
  
  When using the `skimage.transform.rescale` function to downscale an RGB image without explicitly specifying the `channel_axis`, the output image unexpectedly has two channels instead of the standard three. This is observed when applying the function to the standard RGB image from `skimage.data.astronaut()`. The expected output shape for a rescaled RGB image is `(height, width, 3)`. However, the observed output shape is `(256, 256, 2)`. Since `channel_axis` is an optional parameter, the default behavior should maintain the number of channels in the input image.
  
  ### Way to reproduce:
  
  ```
  import numpy as np
  from skimage import transform, data
  
  # Load an RGB image
  rgb_image = data.astronaut()
  
  # Rescale the image
  rescaled_image = transform.rescale(rgb_image, 0.5)
  
  # Output the shape
  print(rescaled_image.shape)
  ```
  #### Expected Behavior:
  The output shape should be `(256, 256, 3)` for a correctly rescaled RGB image, preserving the number of channels.
  
  #### Observed Behavior:
  The output shape is `(256, 256, 2)`, indicating a reduction in the number of channels.
  
  ### Version information:
  
  ```Shell
  3.9.6 (default, Mar 10 2023, 20:16:38) 
  [Clang 14.0.3 (clang-1403.0.22.14.1)]
  macOS-13.3.1-x86_64-i386-64bit
  scikit-image version: 0.22.0
  numpy version: 1.26.2
  ```
  