Fix already-known remote private toots not being searchable by URL (#12336)

* Fix already-known remote private toots not being searchable by URL

Whenever an URL search fails, and an account is provided, try getting a
private status matching that URL from database.

* Fix searching by `id` field instead of `uri`

app/services/resolve_url_service.rb

@@ -24,6 +24,12 @@ class ResolveURLService < BaseService
       status = FetchRemoteStatusService.new.call(resource_url, body, protocol)
       authorize_with @on_behalf_of, status, :show? unless status.nil?
       status
+    elsif fetched_resource.nil? && @on_behalf_of.present?
+      # It may happen that the resource is a private toot, and thus not fetchable,
+      # but we can return the toot if we already know about it.
+      status = Status.find_by(uri: @url) || Status.find_by(url: @url)
+      authorize_with @on_behalf_of, status, :show? unless status.nil?
+      status
     end
   end