Fix search bar dropdown display

[alepbloyd]

If a user is logged in, they can select from different pools to search from (All of GW ScholarSpace, My Works, My Collections).

No matter which of these you select, the dropdown indicator still says All, but it does properly change the search behavior.

@maxturer - Tagging you since you probably have most familiarity with this, but no idea how simple/complex a fix it'll turn out to be.

[maxturer]

Solved this: Span element for the button is missing data-search-element="label" (the screenreadee only element has this already and changes accordingly). Adding this fixes the issue, so I'll add it to upcoming misc PR.