chore: drop redundant allow(unreachable_pub) on version field

The module is `cfg`-gated `pub`/`pub(crate)` and the parent struct is
`#[internal_api]`, so plain `pub` fields don't trigger the lint. Same
pattern as `ParsedLogPath`. Confirmed by `cargo clippy --tests -- -D warnings`
on both feature configs.

Co-authored-by: Isaac

Author: gotocoding-DB

kernel/src/last_checkpoint_hint.rs

@@ -40,7 +40,6 @@ pub(crate) struct LastCheckpointHintSummary {
 #[internal_api]
 pub(crate) struct LastCheckpointHint {
     /// The version of the table when the last checkpoint was made.
-    #[allow(unreachable_pub)] // used by acceptance tests (TODO make an fn accessor?)
     pub version: Version,
     /// The number of actions that are stored in the checkpoint.
     pub size: i64,