Description of problem:
Can't disable a rhel 8 repository on Satellite 6.8 if it was enabled on older Satellite version (Satellite 6.6 and older). This issue is caused by incorrect arch that Satellite uses to resolve all RHEL 8 repos. The database is storing "x86_64" but Satellite is looking for "noarch" when disabling the repository. Therefore, "Repository not found" error is raised. This is affecting the RHEL 8 repositories that were enabled on older Satellite version (Satellite 6.6 and older). When enabling a RHEL 8 repository, the older Satellite version will set its arch to "x86_64". However, Satellite 6.8 will set its arch to "noarch".

Steps to Reproduce:
1. Enable a rhel 8 repository on Satellite 6.6, such as rhel 8 baseos or appstreams
2. Upgrade the Satellite to 6.8
3. Disable the rhel 8 repository

Actual results:
Repository not found

Expected results:
Repository can be disabled successfully

Additional info:

This issue can be workaround by changing the root repo's arch from x86_64 to noarch.

foreman-rake console
Katello::RootRepository.where(name: ["Red Hat Enterprise Linux 8 for x86_64 - BaseOS RPMs x86_64 8", "Red Hat Enterprise Linux 8 for x86_64 - AppStream RPMs x86_64 8", "Red Hat Satellite Tools 6.7 for RHEL 8 x86_64 RPMs x86_64"]).update_all(arch: "noarch")
exit