[Glitch] Improve dropdown menu keyboard navigation

Port a12f1a0baf to glitch-soc

Signed-off-by: Thibaut Girka <thib@sitedethib.com>

app/javascript/flavours/glitch/reducers/modal.js

@@ -10,7 +10,7 @@ export default function modal(state = initialState, action) {
   case MODAL_OPEN:
     return { modalType: action.modalType, modalProps: action.modalProps };
   case MODAL_CLOSE:
-    return initialState;
+    return (action.modalType === undefined || action.modalType === state.modalType) ? initialState : state;
   default:
     return state;
   }