Fix no-js reply

Passing no workflow id along meant that the workflow was loaded via page title
only, resulting in the 'discussion' workflow being loaded, which resulted in
HeaderBlock, TopicListBlock & BoardHistoryBlock being created.
Since we're replying, we actually want workflow of type 'topic' loaded (which
creates TopicBlock). TopicBlock knows how to handle the submitted reply.

Bug: 65639
Change-Id: Ic4d975d9ae08b54bb40ff0a0d4339738a7b23af6