insights: Use patterntype:literal for all queries unless otherwise defined
Created by: CristinaBirkel
Closes: https://github.com/sourcegraph/sourcegraph/issues/38439
This change is to make sure that we preserve the current query behavior even when the search changes to read /.../ syntax as a regular expression.
Test plan
- backfiller jobs are queued up with the
patterntype:literalfield, when that field is not specified - backfiller jobs are queued with whatever
patterntypeis provided, if one is provided