insights: force queries to use patternType:literal if not explicitly defined

Created by: coury-clark

To temporarily preserve the semantic that queries default to patternType:literal after the default changes to patternType:standard we will mutate queries to be patternType:literal if they have no value set before queueing work.

Query builder code: https://sourcegraph.sourcegraph.com/github.com/sourcegraph/sourcegraph/-/blob/enterprise/internal/insights/query/querybuilder/builder.go