This fixes up two issues encountered when running the js-tests, that were introduced with the new admin draft stuff. First, running the test would result in `view-draft=1` being added to the URL query string many many times. The code that does this has been changed to first check if we're running tests at all and not do anything. In the case that we're not in unit tests, we now use `URLSearchParams.set()` instead of `.append()`, which prevents us from having `view-draft` in the query string multiple times. Second, several tests unrelated to the unified banner were failing because there was no dock element available. Most parts of the unified banner will query for the relevant element, and then calls to append to those will fail silently, but for `getDock()` we had an assertion. Since this is just unit tests, we don't care about that, so I've changed the treatment of the dock element to match the other parts of the banner. Testing Done: Ran js-tests and saw that I no longer ended up with `?view-draft=1` in the query string, and did not have a ton of assertion failures in the browser console.