Error code on change password fail due to new password equals old password is not descriptive

## Describe the bug
To show a descriptive error in the Web UI, we need to have a meaningful error code, this is missing currently.


**_Also typo differnt**

## Steps to reproduce
1. Call changeOwnPassword api endpoint with old password is equal to the new one
2. Get an error

## Expected behavior
Error code or innerError code should be descriptive like `errNewPasswordCantEqualOld`

## Actual behavior
Error code not descriptive

## Setup
Please describe how you started the server and provide a list of relevant environment variables or configuration files.

```console
OCIS_XXX=somevalue
OCIS_YYY=somevalue
PROXY_XXX=somevalue
```

## Additional context
Add any other context about the problem here.