Fix ICE for transmutability in candidate assembly

Don't skip transmutability check just because there may be generics in the
ParamEnv.

Fixes #110467

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -775,7 +775,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         obligation: &TraitObligation<'tcx>,
         candidates: &mut SelectionCandidateSet<'tcx>,
     ) {
-        if obligation.has_non_region_param() {
+        if obligation.predicate.has_non_region_param() {
             return;
         }