search: lift global Zoekt query construction
Created by: rvantonder
Stacked on https://github.com/sourcegraph/sourcegraph/pull/25419. Semantics-preserving simplification.
Zoekt query construction (i.e., modification) for global/universal searches can now happen when we construct the request, instead of when we later call request.Search(...)
. This construction can/will go even earlier, but we're not quite ready for that yet. This change is just towards making the state footprint of Search(...)
smaller: Trickling up dependencies => smaller downstream footprint.