pageserver: tolerate loading empty tenants from remote storage

pageserver/src/tenant.rs

@@ -794,10 +794,6 @@ impl Tenant {
             }
         }
 
-        if timeline_ancestors.is_empty() {
-            anyhow::bail!("no valid timelines found on the remote storage")
-        }
-
         // For every timeline, download the metadata file, scan the local directory,
         // and build a layer map that contains an entry for each remote and local
         // layer file.

pageserver/src/tenant/remote_timeline_client/download.rs

@@ -183,10 +183,6 @@ pub async fn list_remote_timelines(
     )
     .await?;
 
-    if timelines.is_empty() {
-        anyhow::bail!("no timelines found on the remote storage")
-    }
-
     let mut timeline_ids = HashSet::new();
 
     for timeline_remote_storage_key in timelines {