Fix non implemented case in LinearExpression class (#724)

Operation `Float *  LinearExpression` is not implemented and caused a stack recursion error `"maximum recursion depth exceeded"`. 
This PR changes to the equivalent `LinearExpression * Float` which calls LinearExpression.__mul__ that can handle floats.



## Summary by CodeRabbit

* **Bug Fixes**
  * Fixed scalar multiplication operations on linear expressions to deliver correct mathematical results in linear programming problems.

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Authors:
  - Hugo Linsenmaier (https://github.com/hlinsen)

Approvers:
  - Ishika Roy (https://github.com/Iroy30)

URL: #724

Author: hlinsen

python/cuopt/cuopt/linear_programming/problem.py

@@ -935,7 +935,7 @@ def __mul__(self, other):
                 return other * self
 
     def __rmul__(self, other):
-        return other * self
+        return self * other
 
     def __itruediv__(self, other):
         # Compute expr /= constant