Update the user with existing name and username.

When you are updating the user with existing name and username, you are getting an error message "A user with that username already exists."
**To Reproduce**

Steps to reproduce the behavior:

Current username: zxcvbnm
Updating username to: zxcvbnm,
Current name: zxcvbnm
Updating name to: zxcvbnm,

1. Go to 'User-update user profile'.
2. Provide the access token.
3. .{
"name": "zxcvbnm",
"username": "zxcvbnm",
"bio": "string",
"location": "string",
"occupation": "string",
"organization": "string",
"slack_username": "string",
"social_media_links": "string",
"skills": "string",
"interests": "string",
"resume_url": "string",
"photo_url": "string",
"need_mentoring": true,
"available_to_mentor": true
}
4. Click on 'Execute'.
5. Scroll down to 'Responses'.
6.

**Expected behavior**
It should either be successfully updated message or a message like "no fields have been updated". Also the error message being shown now is not listed under responses.

**Desktop (please complete the following information):**
- OS: Windows 10
- Browser chrome