Fix pending upload count not being decremented on error (#12499)

The arguments were passed to the wrong function… also, there is no
need to have a conditional decrementation: failure to upload means
we marked an upload as pending, in all cases.

app/javascript/mastodon/actions/compose.js

@@ -236,7 +236,7 @@ export function uploadCompose(files) {
             dispatch(uploadComposeProgress(progress.reduce((a, v) => a + v, 0), total));
           },
         }).then(({ data }) => dispatch(uploadComposeSuccess(data, f)));
-      }).catch(error => dispatch(uploadComposeFail(error, true)));
+      }).catch(error => dispatch(uploadComposeFail(error)));
     };
   };
 };
@@ -267,11 +267,10 @@ export function changeUploadComposeSuccess(media) {
   };
 };
 
-export function changeUploadComposeFail(error, decrement = false) {
+export function changeUploadComposeFail(error) {
   return {
     type: COMPOSE_UPLOAD_CHANGE_FAIL,
     error: error,
-    decrement: decrement,
     skipLoading: true,
   };
 };

app/javascript/mastodon/reducers/compose.js

@@ -328,7 +328,7 @@ export default function compose(state = initialState, action) {
   case COMPOSE_UPLOAD_SUCCESS:
     return appendMedia(state, fromJS(action.media), action.file);
   case COMPOSE_UPLOAD_FAIL:
-    return state.set('is_uploading', false).update('pending_media_attachments', n => action.decrement ? n - 1 : n);
+    return state.set('is_uploading', false).update('pending_media_attachments', n => n - 1);
   case COMPOSE_UPLOAD_UNDO:
     return removeMedia(state, action.media_id);
   case COMPOSE_UPLOAD_PROGRESS: