fix(python/geometry): Prevent cast_to_single from casting integers to float32 (#678)

[Paramveersingh-S]

Description

Fixes issue #678 where Geometry.cast_to_single() forcefully cast integers and lists of integers into np.float32, which inadvertently corrupts integer-based attributes and crashes memory allocations in algorithms like sart.

Changes made

• Added a robust dtype check using np.issubdtype to gracefully intercept and ignore pure integers and arrays of integers.
• Floats and float arrays are still correctly cast to single precision.
• No changes required to the exclude_from_cast hardcoded array, preventing this issue from occurring on any custom integer variables users might attach to the Geometry object.

[AnderBiguri]

ah thanks! I assume this is one of those numpy 2.4 caused issues, which is why I didn't catch it.