fix: Handle errors without response (#4274)

app/javascript/mastodon/actions/statuses.js

@@ -113,7 +113,7 @@ export function fetchContext(id) {
       dispatch(fetchContextSuccess(id, response.data.ancestors, response.data.descendants));
 
     }).catch(error => {
-      if (error.response.status === 404) {
+      if (error.response && error.response.status === 404) {
         dispatch(deleteFromTimelines(id));
       }
 

app/javascript/mastodon/actions/timelines.js

@@ -105,7 +105,7 @@ export function refreshTimelineFail(timeline, error, skipLoading) {
     timeline,
     error,
     skipLoading,
-    skipAlert: error.response.status === 404,
+    skipAlert: error.response && error.response.status === 404,
   };
 };