[MM-62986][MM-63011][MM-63013][MM-63014][MM-63018] Various accessibility fixes around login, account creation and MFA setup (#30847)

* [MM-62986] Ensure focus goes back to the inputs after an error for Login/Create Account/MFA

* [MM-63011] Show outline on Mattermost logo link when focused

* [MM-63018] Remove tabindex from the login/signup cards and use <form> element for submit

* [MM-63014] Toggle aria-label when show/hide password is pressed

* [MM-63013] Mention the field name when showing an error message about the password field

* Fix lint

* Update screenshots and fix tests

* Update screenshots and fix tests

* Fix tests

* Update webapp/channels/src/components/mfa/setup/setup.tsx

Co-authored-by: Harrison Healey <harrisonmhealey@gmail.com>

* update screenshots

---------

Co-authored-by: yasserfaraazkhan <attitude3cena.yf@gmail.com>
Co-authored-by: Harrison Healey <harrisonmhealey@gmail.com>

e2e-tests/cypress/tests/integration/channels/system_console/user_management/users_spec.js

@@ -164,7 +164,7 @@ describe('System Console > User Management > Users', () => {
 
         // * Verify the appropriate error is returned.
         cy.get('form.form-horizontal').find('.has-error p.error').should('be.visible').
-            and('contain', 'Must be 5-72 characters long.');
+            and('contain', 'Your password must be 5-72 characters long.');
     });
 
     it('MM-T936 Users - System admin changes own password - Blank fields', () => {
@@ -193,7 +193,7 @@ describe('System Console > User Management > Users', () => {
 
         // * Verify the appropriate error is returned.
         cy.get('form.form-horizontal').find('.has-error p.error').should('be.visible').
-            and('contain', 'Must be 5-72 characters long.');
+            and('contain', 'Your password must be 5-72 characters long.');
     });
 
     it('MM-T937 Users - System admin changes own password - Successfully changed', () => {