`sino_360_to_180` method changing data shape breaks GPU loop

The `sino_360_to_180` method method from httomolibgpu cuts and stitches a 360 sinogram into a 180 sinogram, and this is inherently an operation that changes the shape of the data (the sinogram typically becomes significantly bigger in the horizontal direction, and half as small in the vertical direction).

If this method is at the end of a section then (by design of the GPU loop), httomo would attempt to overwrite the input array with this output. However, this will typically produce an error due to the change in data shape, similar to what happens with recon methods that was naively addressed in 99918b5.

If `sino_360_to_180` is able to output the correct data shape, then the maximum number of slices calculation can also take into account this data shape change, and would help httomo be able to run this method without any issues with memory estimation.

However, at the moment, the stitching method does not work in the `gpuloop` branch of httomo. See the following issue for more info about enabling the stitching method from httomolibgpu to run in the `gpuloop` branch of httomo: https://github.com/DiamondLightSource/httomolibgpu/issues/107