Deleting a collection should detach associated drafts from it (#5082)

Co-authored-by: Tom Moor <tom.moor@gmail.com>

server/models/helpers/SearchHelper.ts

@@ -31,7 +31,7 @@ type SearchOptions = {
   /** The query offset for pagination */
   offset?: number;
   /** Limit results to a collection. Authorization is presumed to have been done before passing to this helper. */
-  collectionId?: string;
+  collectionId?: string | null;
   /** Limit results to a shared document. */
   share?: Share;
   /** Limit results to a date range. */