Importing project from GitHub fails when Wiki is enabled but empty and Gitaly's `import_repository` is enabled.

When the import_repository feature flag for Gitaly is enabled. Importing a repository from GitHub fails if the project has an empty wiki.

When the project has wiki's enabled the has_wiki flag that we use to determine if we should import the wiki is true. GitHub documentation

We used to ignore this error when the output would be something matching from gitlab shell would match repository not exported, but when this Gitaly endpoint is enabled, the failure would look like CreateRepositoryFromURL: clone cmd wait: exit status 128.

Because then the import is marked as failed, further steps are not performed: Issues and Pull requests are not performed.

Steps to reproduce:

• Setup OAuth with GitHub
• Login using a GitHub Account
• Try to import a project that has Wiki enabled, but no wiki repository: For example: https://github.com/Reprazent/test-repo/
• See the import fail

The import_repository feature flag is currently not enabled on GitLab.com.