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.

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.