gh-41017: Fix an incorrect comparison in crypto/sbox
    
detected by the compiler

```
warning: self-comparison always evaluates to true [-Wtautological-
compare]
```


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preview.

### ⌛ Dependencies

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URL: #41017
Reported by: user202729
Reviewer(s): Lorenz Panny

Author: Release Manager

src/sage/crypto/sbox.pyx

@@ -252,7 +252,7 @@ cdef class SBox(SageObject):
             raise NotImplemented
 
         cdef SBox other = <SBox> rhs
-        return (self._S_list == other._S_list) and (self._big_endian == self._big_endian)
+        return (self._S_list == other._S_list) and (self._big_endian == other._big_endian)
 
     def __ne__(self, other):
         """