Mm 62677 - modal focus management - find channels modal (#29957)

* MM-62312 - modal focus management; revamp quick switch channel modal!

* get quick switch test working

* configure the generic modal to accept refs to focus within and onhide to the origin element

* apply pr feedback, get modal element get autofocus, use id instead of ref

* update more direct channels modal to use generic modal

* fix unit tests and snapshots

* fix unit tests

* fix modal margin top to fit in smaller screens

* fix e2e test

* remove unnecesary onexited extra call

* fix e2e tests

* set correct label

* fix snapshots

* create helper function for sending custom focus event

* migrate quick switch modal to use new approach to focus

* migrate more direct channels modal to new approach

* fix snapshots

* fix types

* fix modal closing behavior

* fix snapshots

* fix cypress tests

* remove only

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

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

@@ -142,7 +142,9 @@ describe('Verify Guest User Identification in different screens', () => {
         });
 
         // # Close Dialog
-        cy.get('#quickSwitchModalLabel > .close').click();
+        cy.get('#quickSwitchModal').within(() => {
+            cy.get('button.close[aria-label="Close"]').click();
+        });
     });
 
     it('MM-T1377 Verify Guest Badge in DM Search dialog', () => {