MM-59065 - New channel menu using new menu system (#30093)

* New channel menu using new menu system

* fix e2e-tests

* remove extraneous separator

* lint fix

* fix test after merge

* update to pass properties to first menu item

* fix e2etest

* refactor: Update channel header menu items to use const event handlers

* refactor: Extract plugin item click handler in channel header menu

* refactor: Improve error handling and button click handlers in mobile channel header plugins

* lint fixes

* updates for code reveiw

* run i18n-extract

* fix unit test

* fix: Close channel dropdown menu by clicking channel header title

* fix: Use keyboard escape to close channel dropdown menu in e2e tests

* fix cypress test

* fix: Resolve MUI Menu component fragment rendering issue

* cleanup

* remove unneccessary css

* fixing testing issues

---------

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

e2e-tests/cypress/tests/integration/channels/enterprise/guest_accounts/guest_identification_ui_spec.ts

@@ -59,8 +59,8 @@ describe('Verify Guest User Identification in different screens', () => {
 
     it('MM-T1370 Verify Guest Badge in Channel Members dropdown and dialog', () => {
         // # Open Channel Members RHS
-        cy.get('#channelHeaderDropdownIcon').click();
-        cy.get('#channelManageMembers').click().wait(TIMEOUTS.HALF_SEC);
+        cy.get('#channelHeaderTitle').click();
+        cy.get('#channelMembers').click().wait(TIMEOUTS.HALF_SEC);
         cy.uiGetRHS().findByTestId(`memberline-${guestUser.id}`).within(($el) => {
             cy.wrap($el).get('.Tag').should('be.visible').should('have.text', 'GUEST');
         });