models: explicitely save procedure's new revision

Deep-cloned objects have all their relationships stale. Thus, for a
newly deep-cloned revision, `revision.types_de_champs` returns `[]`,
even when it actually has associated types de champ.

This causes consecutive champs creations and re-ordering to fail in
subtle ways, like:

```
procedure.draft_revision.add_type_de_champ(…)
procedure.publish_revision!
procedure.draft_revision.add_type_de_champ(…)
procedure.draft_revision.move_type_de_champ(…) # this will fail
```

As `publish_revision!` created a new stale revision, moving the type
de champ fails because not all existing champs are found until the
object is refreshed.

We don't hit this path in production, because usually only a single
operation is made in a request.

To fix this, save the new revision before associating it as the draft
procedure.

(Another option would be to `reload` the revision after creation, but
this seems better contained and matches the name of the method.)

app/models/procedure.rb

@@ -678,7 +678,9 @@ class Procedure < ApplicationRecord
   end
 
   def create_new_revision
-    draft_revision.deep_clone(include: [:revision_types_de_champ, :revision_types_de_champ_private])
+    draft_revision
+      .deep_clone(include: [:revision_types_de_champ, :revision_types_de_champ_private])
+      .tap(&:save!)
   end
 
   def average_dossier_weight