Add chained comparison TypeError test for Expr

Added a test to ensure that chained comparisons involving Expr objects raise a TypeError, improving test coverage for invalid operations.

Author: Zeroto521

tests/test_Expr.py

@@ -335,6 +335,9 @@ def test_le(model):
     with pytest.raises(TypeError):
         expr1 <= "invalid"
 
+    with pytest.raises(TypeError):
+        1 <= expr1 <= 1
+
 
 def test_ge(model):
     m, x, y = model