FIX: lint issues in config migration

Author: wozulong

db/migrate/20250110114305_embedding_config_data_migration.rb

@@ -171,11 +171,7 @@ def model_attrs(model_name)
   end
 
   def persist_config(attrs)
-    provider_params_json = if attrs[:provider_params].present?
-      attrs[:provider_params].to_json
-    else
-      nil
-    end
+    provider_params_json = attrs[:provider_params].to_json if attrs[:provider_params].present?
 
     DB.exec(
       <<~SQL,