[Glitch] Unliking a post updates like count on front end

Port a9530e29a2 to glitch-soc

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

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

@@ -3,6 +3,7 @@ import {
   REBLOG_FAIL,
   FAVOURITE_REQUEST,
   FAVOURITE_FAIL,
+  UNFAVOURITE_SUCCESS,
   BOOKMARK_REQUEST,
   BOOKMARK_FAIL,
 } from 'flavours/glitch/actions/interactions';
@@ -39,6 +40,9 @@ export default function statuses(state = initialState, action) {
     return importStatuses(state, action.statuses);
   case FAVOURITE_REQUEST:
     return state.setIn([action.status.get('id'), 'favourited'], true);
+  case UNFAVOURITE_SUCCESS:
+    const favouritesCount = action.status.get('favourites_count');
+    return state.setIn([action.status.get('id'), 'favourites_count'], favouritesCount - 1);
   case FAVOURITE_FAIL:
     return state.get(action.status.get('id')) === undefined ? state : state.setIn([action.status.get('id'), 'favourited'], false);
   case BOOKMARK_REQUEST: