feat(tvix/store/pathinfosvc): derive Clone

This allows closing a TvixStoreIO if it contains a SledPathInfoService.

Change-Id: Ife451eda331bafdb1af91f45a94cccd13f2f67c6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8620
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI

tvix/store/src/pathinfoservice/sled.rs

@@ -8,6 +8,7 @@ use tracing::warn;
 ///
 /// The PathInfo messages are stored as encoded protos, and keyed by their output hash,
 /// as that's currently the only request type available.
+#[derive(Clone)]
 pub struct SledPathInfoService {
     db: sled::Db,
 }