Remove unused prop

Summary:
While reading through the Inspector I found this prop passed down and not used anywhere

printer_shredder

Reviewed By: Katalune

Differential Revision: D22431895

fbshipit-source-id: 6cbc97b3faec26349a1ad900ffa455e95f53bb2b

desktop/plugins/leak_canary/index.tsx

@@ -200,7 +200,6 @@ export default class LeakCanary<PersistedState> extends FlipperPlugin<
                     onElementExpanded={(eid /*, deep*/) => {
                       this._toggleElement(idx, eid);
                     }}
-                    onValueChanged={() => {}}
                     selected={selected}
                     searchResults={null}
                     root={leak.root}