App config > "Docker Build Config" page shows error if container registry is not configured

[uxarya-d]

Checklist:

• I've searched in the docs and FAQ for my answer
• I've included steps to reproduce the bug.

Describe the bug

If container registry is not configured, Docker Build Config page in App Configuration breaks

To Reproduce

[ordered list the process to finding and recreating the issue, example below]

1. Create an application (Do not configure the app yet)
2. Delete all container registry configurations from global configuration (To be able to delete a container registry, it should not be used in any application)
3. Revisit the app created in Step 1; Go to App Config > Docker Build Config

Expected behavior

In this case, the Git Docker Build Config > Container Registry dropdown should have been empty as there was no container registry was present.
We already have a "Add Container Registry" option in the dropdown which navigates the user to Global Config > Container Registry.

Current behavior

The page breaks showing the message "We encountered an error"