R1:58b889c5b056

Make the default ApplicationSearch query explicit, not just the first item in the list

Summary:
Ref T12956. Currently, when you visit `/maniphest/` (or any other ApplicationSearch application) we execute the first query in the list by default.

In T12956, I plan to make changes so that personal queries are always first, then global/builtin queries. Without changing the "default query" rule, this will make it harder to have, for example, some custom queries in Differential but still run a global query like…