feat: Add the frontend support for MFA (#12372)

FE support for https://github.com/chatwoot/chatwoot/pull/12290
## Linear:
- https://github.com/chatwoot/chatwoot/issues/486

## Description
This PR implements Multi-Factor Authentication (MFA) support for user
accounts, enhancing security by requiring a second form of verification
during login. The feature adds TOTP (Time-based One-Time Password)
authentication with QR code generation and backup codes for account
recovery.

## Type of change

- [ ] New feature (non-breaking change which adds functionality)

## How Has This Been Tested?

- Added comprehensive RSpec tests for MFA controller functionality
- Tested MFA setup flow with QR code generation
- Verified OTP validation and backup code generation
- Tested login flow with MFA enabled/disabled

## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Pranav <pranav@chatwoot.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: Sojan Jose <sojan@pepalo.com>

app/javascript/dashboard/api/mfa.js

@@ -0,0 +1,28 @@
+/* global axios */
+import ApiClient from './ApiClient';
+
+class MfaAPI extends ApiClient {
+  constructor() {
+    super('profile/mfa', { accountScoped: false });
+  }
+
+  enable() {
+    return axios.post(`${this.url}`);
+  }
+
+  verify(otpCode) {
+    return axios.post(`${this.url}/verify`, { otp_code: otpCode });
+  }
+
+  disable(password, otpCode) {
+    return axios.delete(this.url, {
+      data: { password, otp_code: otpCode },
+    });
+  }
+
+  regenerateBackupCodes(otpCode) {
+    return axios.post(`${this.url}/backup_codes`, { otp_code: otpCode });
+  }
+}
+
+export default new MfaAPI();