Allow `getCiConfigData` graphQL query to work in projects with no sha

Because we now allow user to start working on their Ci configuration from the pipeline editor, we can run into a usecase where the user starts working on an uncommitted CI config file. When they do, we send the text editor content to the API to lint and get the results back, however we get an error that:

Internal servor error: undefined method sha for nil:NilClass

It seems like there is a dependency between having a repository and linting. Given that we can use linting with file content now, we should make sure we can lint a CI configuration without a repository.