Change importer flag to act as default (disabled)
This change switches the large-github-import
job to use the default
state of the github_importer_lower_per_page_limit
flag, which is
disabled.
This is to run the tests using the same flag state as a GitLab Dedicated instance, which cannot have flag states toggled, to more closely QA a large GitHub import for a customer who is migrating to Dedicated.