Make collab quieter on startup (#8685)

Fix initialization of minio to happen on service start instead of
bootstrap,
don't log errors if extensions are empty or if clickhouse is disabled

Release Notes:

- N/A

crates/collab/src/api/extensions.rs

@@ -147,9 +147,7 @@ async fn fetch_extensions_from_blob_store(
         .send()
         .await?;
 
-    let objects = list
-        .contents
-        .ok_or_else(|| anyhow!("missing bucket contents"))?;
+    let objects = list.contents.unwrap_or_default();
 
     let mut published_versions = HashMap::<&str, Vec<&str>>::default();
     for object in &objects {