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

啟用 "user.password.reset.enabled" 後，首先從 UI 追蹤 CloudStack 的密碼重設流程。檢查提交的密碼在哪裡進行驗證，並確認重設為現有密碼會被拒絕，將重現步驟和預期行為作為完成標準。

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