[MM-61361] Force reconnect handler to fetch channel categories on reconnect (#29010)

Co-authored-by: Mattermost Build <build@mattermost.com>

webapp/channels/src/actions/websocket_actions.jsx

@@ -237,6 +237,7 @@ export function reconnect() {
 
         dispatch(loadChannelsForCurrentUser());
         dispatch(fetchAllMyChannelMembers());
+        dispatch(fetchMyCategories(currentTeamId));
 
         if (mostRecentPost) {
             dispatch(syncPostsInChannel(currentChannelId, mostRecentPost.create_at));

webapp/channels/src/actions/websocket_actions.test.jsx

@@ -2,6 +2,7 @@
 // See LICENSE.txt for license information.
 
 import {UserTypes, CloudTypes} from 'mattermost-redux/action_types';
+import {fetchMyCategories} from 'mattermost-redux/actions/channel_categories';
 import {getGroup} from 'mattermost-redux/actions/groups';
 import {
     getPostThreads,
@@ -44,6 +45,11 @@ jest.mock('mattermost-redux/actions/posts', () => ({
     getMentionsAndStatusesForPosts: jest.fn(),
 }));
 
+jest.mock('mattermost-redux/actions/channel_categories', () => ({
+    ...jest.requireActual('mattermost-redux/actions/channel_categories'),
+    fetchMyCategories: jest.fn(),
+}));
+
 jest.mock('mattermost-redux/actions/status_profile_polling', () => ({
     ...jest.requireActual('mattermost-redux/actions/status_profile_polling'),
     batchFetchStatusesProfilesGroupsFromPosts: jest.fn(() => ({type: ''})),
@@ -637,6 +643,11 @@ describe('reconnect', () => {
         reconnect();
         expect(syncPostsInChannel).toHaveBeenCalledWith('otherChannel', '12345');
     });
+
+    test('should call fetchMyCategories when socket reconnects', () => {
+        reconnect();
+        expect(fetchMyCategories).toHaveBeenCalledWith('currentTeamId');
+    });
 });
 
 describe('handleChannelUpdatedEvent', () => {