[MM-63007][MM-63004][MM-63020][MM-63009][MM-63008] More accessibility fixes around Search (#31409)

* [MM-63008] Make collapse button on search bar an actual button

* [MM-63004][MM-63020] Convert search box to floating-ui, fix some of the roles and labels that were incorrect

* [MM-63009] Add radiogroup and radio roles to the search box types

* [MM-63007] Ensure search box reads out number of results with suggestion items

* Fix playwright tests

* PR feedback

* Remove floating ui overlay

* Remove unnecessary .first() by being more specific about the search box

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

e2e-tests/cypress/tests/support/ui/global_header.js

@@ -104,7 +104,7 @@ Cypress.Commands.add('uiGetSearchContainer', () => {
 });
 
 Cypress.Commands.add('uiGetSearchBox', () => {
-    return cy.get('.search-bar').should('be.visible');
+    return cy.findByRole('searchbox').should('be.visible');
 });
 
 Cypress.Commands.add('uiGetRecentMentionButton', () => {