## Description
The current password reset endpoint returns different HTTP status codes
and messages depending on whether the email exists in the system (200
for existing emails, 404 for non-existing ones). This allows attackers
to enumerate valid email addresses via the password reset form.
## Changes
### `app/controllers/devise_overrides/passwords_controller.rb`
- Removed the `if/else` branch that returned different responses based
on email existence
- Now always returns a generic `200 OK` response with the same message
regardless of whether the email exists
- Uses safe navigation operator (`&.`) to send reset instructions only
if the user exists
### `config/locales/en.yml`
- Consolidated `reset_password_success` and `reset_password_failure`
into a single generic `reset_password` key
- New message does not reveal whether the email exists in the system
## Security Impact
- **Before**: An attacker could determine if an email was registered by
observing the HTTP status code (200 vs 404) and response message
- **After**: All requests receive the same 200 response with a generic
message, preventing user enumeration
This follows [OWASP guidelines for authentication error
messages](https://cheatsheetseries.owasp.org/cheatsheets/Authentication_Cheat_Sheet.html#authentication-responses).
Fixes#13527