Multiple Issues in account setting page

[JanhaviAlekar]

What happened:
When there are multiple invitations, accepting an invite causes the number of "Accept Invitation" buttons to increase.

What you expected to happen:
The number of "Accept Invitation" buttons should remain the same.

What happened:
When deleting a project invite or declining an invite , the dialog does not close after successful deletion.

What you expected to happen:
The dialog box should close after a successful invite deletion.

What happened:
Similarly, when leaving a project, the dialog box should close after successfully leaving the project.

What you expected to happen:
The dialog box should close after successfully leaving a project.

What happened:
When creating a user with an existing username, there is no error message displayed to inform the user that the username already exists.

What you expected to happen:
An error message should be displayed indicating that the username is already taken.

How to reproduce it (as minimally and precisely as possible):
How to reproduce it (as minimally and precisely as possible):

Go to Settings.

1. Create at least three users.
2. Send invites to the users.
3. Try to accept an invite, delete an invite, and leave a project.