Polysat: forbidden intervals updates (#5230)

* Pop assign_eh

* Fix scoped_ptr_vector constructors, add detach()

* Need to copy the returned lemma

* Add test

* Basic inequality tests

* Return disjunctive lemma to caller

src/math/polysat/trail.h

@@ -22,7 +22,8 @@ namespace polysat {
         inc_level_i,
         viable_i,
         assign_i,
-        just_i
+        just_i,
+        assign_eh_i,
     };