Added custom attributes to metadata typing

Summary: These replace tags, and are KV instead. They allow us to send framework specific data that arent common enough to be promoted to the top level, similar to hidden attributes. They will be needed for bloks

Reviewed By: lblasa

Differential Revision: D45079134

fbshipit-source-id: e4962bd56f0c24608504367f50cd796fd3d79fcd

desktop/plugins/public/ui-debugger/types.tsx

@@ -114,7 +114,7 @@ export type Metadata = {
   namespace: string;
   name: string;
   mutable: boolean;
-  tags?: string[];
+  customAttributes?: Record<string, string | number>;
 };
 
 export type Bounds = {