Check credit for users already in the list if the username is added to Credit others

Issue information

From user: nicxvan

Related to !21 (merged)

Contribution record

Fork management

Problem/Motivation

After releasing an episode I credit all participants.
Since I am the one creating the issue I just use the credit others form. I built a tool on talkingdrupal.com to help gather all of the participants: https://talkingdrupal.com/522 on the right sidebar under the credit details dropdown.

Since I create the issue I am already in the list, however when I paste the usernames my box is not checked.

Steps to reproduce

Create an issue.
Edit contribution
Add yourself to credit others
You are not checked

Proposed resolution

If a user is already in the list and added to credit others they should be granted credit.

Remaining tasks

User interface changes

API changes

Data model changes

Edited by drupalbot