Both () and = variants covered. It is important to make sure that
the transaction is a read transaction, so we cannot hide all that logic
inside update_pragma, and have to make our decision before that.
This change refactors how PRAGMA statements are handled, introducing a
more organized and extensible structure to simplify adding new PRAGMA
properties in the future.
Previously, only the `cache_size` PRAGMA was supported. With this
update, support for the `journal_mode` PRAGMA has been added.
