Expose mapColumnValue on session instances

[aleclarson]

As of Jul 27 2025, the sql-js and libsql drivers pass a normalizeFieldValue to the custom result mapper.

drizzle-orm/drizzle-orm/src/libsql/session.ts

Line 373 in c0277c0

function normalizeFieldValue(value: unknown) {

drizzle-orm/drizzle-orm/src/sql-js/session.ts

Line 295 in c0277c0

function normalizeFieldValue(value: unknown) {

It'd be great to expose that function on the SQLiteSession as a method, so libraries can use it. For my particular use case, drizzle-plus allows using RQB queries as subqueries, e.g. using the as() method extension. I need to call mapRelationalRow for the subquery to work, and there are data-mapping edge cases I can't cover without the session's normalizeFieldValue function.