The unified banner attempts to access the draft via the API for the draft when its created, in order to start up its draft modes. When the user does not have access to the draft, this ends up with an error in the JS console. This error was harmless, but annoying to see when debugging. This change adds a catch so we can swalllow any errors when attempting to call ready on the draft. Testing Done: Loaded a review request owned by another user and saw that I no longer got an error in my devtools.