fix(p/demo/uassert): amend ineffective assignment (#2936)

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examples/gno.land/p/demo/uassert/uassert.gno

@@ -266,7 +266,7 @@ func NotEqual(t TestingT, expected, actual interface{}, msgs ...string) bool {
 		if av, ok := actual.(string); ok {
 			notEqual = ev != av
 			ok_ = true
-			es, as = ev, as
+			es, as = ev, av
 		}
 	case std.Address:
 		if av, ok := actual.(std.Address); ok {