pageserver: clean up a TODO comment (#6282)

These functions don't need updating for sharding: it's fine for them to
remain shard-naive, as they're only used in the context of dumping a
layer file. The sharding metadata doesn't live in the layer file, it
lives in the index.

Author: jcsp

pageserver/src/tenant/storage_layer/delta_layer.rs

@@ -320,8 +320,8 @@ impl DeltaLayer {
             .metadata()
             .context("get file metadata to determine size")?;
 
-        // TODO(sharding): we must get the TenantShardId from the path instead of reading the Summary.
-        // we should also validate the path against the Summary, as both should contain the same tenant, timeline, key, lsn.
+        // This function is never used for constructing layers in a running pageserver,
+        // so it does not need an accurate TenantShardId.
         let tenant_shard_id = TenantShardId::unsharded(summary.tenant_id);
 
         Ok(DeltaLayer {

pageserver/src/tenant/storage_layer/image_layer.rs

@@ -278,8 +278,8 @@ impl ImageLayer {
             .metadata()
             .context("get file metadata to determine size")?;
 
-        // TODO(sharding): we should get TenantShardId from path.
-        // OR, not at all: any layer we load from disk should also get reconciled with remote IndexPart.
+        // This function is never used for constructing layers in a running pageserver,
+        // so it does not need an accurate TenantShardId.
         let tenant_shard_id = TenantShardId::unsharded(summary.tenant_id);
 
         Ok(ImageLayer {