[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/playwright/lib/src/ui/pages/login.ts

@@ -37,7 +37,7 @@ export default class LoginPage {
         this.loginPlaceholder = page.locator(`[placeholder="Email or Username"]`);
         this.loginWithAdLdapPlaceholder = page.locator(`[placeholder="Email, Username or AD/LDAP Username"]`);
         this.passwordInput = page.locator('#input_password-input');
-        this.passwordToggleButton = page.getByRole('button', {name: 'Show or hide password'});
+        this.passwordToggleButton = page.locator('#password_toggle');
         this.signInButton = page.locator('button:has-text("Log in")');
         this.createAccountLink = page.locator("text=Don't have an account?");
         this.forgotPasswordLink = page.locator('text=Forgot your password?');

e2e-tests/playwright/lib/src/ui/pages/signup.ts

@@ -40,7 +40,7 @@ export default class SignupPage {
         this.emailInput = page.locator('#input_email');
         this.usernameInput = page.locator('#input_name');
         this.passwordInput = page.locator('#input_password-input');
-        this.passwordToggleButton = page.getByRole('button', {name: 'Show or hide password'});
+        this.passwordToggleButton = page.locator('#password_toggle');
         this.createAccountButton = page.locator('button:has-text("Create Account")');
         this.emailError = page.locator('text=Please enter a valid email address');
         this.usernameError = page.locator(