No validation done when user resets a password

### The required feature described as a wish

Steps to reproduce the issue

1. Enable the global setting "user.password.reset.enabled"

2. Click on forgot password option from the UI

3. User provides the same password, Cloudstack doesn't validate the password and sets the same password for the user

Expected behaviour

Cloudstack should validate if the same password is used for reset password, this can prevent security related issues

启用 "user.password.reset.enabled" 后，首先从 UI 跟踪 CloudStack 的密码重置流程。检查提交的密码在哪里进行验证，并确认重置为现有密码会被拒绝，将复现步骤和预期行为作为完成标准。

由索引模型根据 Issue 内容生成。