Solver: Mage: Fix empty HS error and space in input param.

src/Solver/Mage.py

@@ -462,6 +462,9 @@ class Mage(CommandLineSolver):
             files.append(f"{name}.SIN")
 
             for hs in hydraulic_structures:
+                if hs.input_reach is None:
+                    continue
+
                 if not hs.input_reach.is_enable():
                     continue