support in list_flows, flows that have no last flow_version

backend/windmill-common/src/flows.rs

@@ -56,8 +56,8 @@ pub struct ListableFlow {
     pub path: String,
     pub summary: String,
     pub description: String,
-    pub edited_by: String,
-    pub edited_at: chrono::DateTime<chrono::Utc>,
+    pub edited_by: Option<String>,
+    pub edited_at: Option<chrono::DateTime<chrono::Utc>>,
     pub archived: bool,
     pub extra_perms: serde_json::Value,
     pub starred: bool,