Default repository not preselected in Create Issue modal

[arush-vashishtha]

After setting a default repository with /github default-repo set , running /github issue create opens the issue creation modal, but the default repository is not preselected in the Repository option.

Steps to reproduce:

• Connect GitHub to Mattermost.
• Create a webhook for a repository.
• Set that repository as default using /github default-repo set.
• Run /github issue create.

Expected Result:
In the Create Issue modal, the default repository that was set should already be selected in the Repository option.

Actual Result:
The Create Issue modal opens, but the default repository is not preselected in the Repository option.