clients/shell/src/chat: Add new arg to NewMountTableDispatcher
clients/shell/src/chat: Add new arg to NewMountTableDispatcher

See: https://vanadium-review.googlesource.com/#/c/9878

MultiPart: 3/3
Change-Id: Ib20b5c511fe7607200833a86d174ba1c3f30a24a

viksit/chat,vanadium/chat,viksit/chat,vanadium/chat,viksit/chat,viksit/chat,viksit/chat,vanadium/chat,vanadium/chat,vanadium/chat