Why does installing leapp in a Satellite 6.11 running on RHEL 7 fail with package dependency issues?

Issue

• The Satellite 6.11 Upgrading and Updating Red Hat Satellite guide instructs in its Chapter 4. Upgrading Satellite or Capsule to Red Hat Enterprise Linux 8 In-Place Using Leapp to enable repository rhel-7-server-extras-rpms and to install leapp running command "satellite-maintain packages install leapp leapp-repository".

• Why does the installation of leapp fail with unsatisfied package dependencies?

# satellite-maintain packages install leapp leapp-repository
Running install packages in unlocked session
================================================================================
Confirm installer run is allowed:

WARNING: This script runs satellite-installer after the yum execution
to ensure the Satellite is in a consistent state.
As a result some of your services may be restarted.

Do you want to proceed?, [y(yes), q(quit)] y
                                                                      [OK]
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Unlock packages:                                                      [OK]
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Install packages: Loaded plugins: product-id, search-disabled-repos, subscription-manager
Package leapp-repository is obsoleted by leapp-upgrade-el7toel8, trying to install leapp-upgrade-el7toel8-0.18.0-3.el7_9.noarch instead
Resolving Dependencies
[...]
Error: Package: libdnf-0.22.5-2.el7_9.x86_64 (rhel-7-server-extras-rpms)
           Requires: libsolvext.so.0()(64bit)
           Available: libsolv-0.6.11-1.el7.x86_64 (rhel-7-server-rpms)
               libsolvext.so.0()(64bit)
           Available: libsolv-0.6.20-5.el7.x86_64 (rhel-7-server-rpms)
               libsolvext.so.0()(64bit)
           Available: libsolv-0.6.26-1.el7.x86_64 (rhel-7-server-rpms)
               libsolvext.so.0()(64bit)
           Available: libsolv-0.6.26-2.el7.x86_64 (rhel-7-server-rpms)
               libsolvext.so.0()(64bit)
           Available: libsolv-0.6.34-2.el7.x86_64 (rhel-7-server-rpms)
               libsolvext.so.0()(64bit)
           Available: libsolv-0.6.34-4.el7.x86_64 (rhel-7-server-rpms)
               libsolvext.so.0()(64bit)
           Installed: libsolv-0.7.22-1.el7pc.x86_64 (@rhel-7-server-satellite-6.11-rpms)
              ~libsolvext.so.1()(64bit)
[...]
**********************************************************************
Dependency resolving failed due to missing dependencies.
Some repositories on your system are disabled, but yum can enable them
and search for missing dependencies. This will require downloading
metadata for disabled repositories and may take some time and traffic.
**********************************************************************
[...]
 You could try using --skip-broken to work around the problem
 You could try running: rpm -Va --nofiles --nodigest
                                                    [WARNING]
Failed executing yum --disableplugin=foreman-protector install leapp leapp-repository, exit status 1
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[...]
Scenario [install packages in unlocked session] failed.

The following steps ended up in warning state:

  [packages-install]

The steps in warning state itself might not mean there is an error,
but it should be reviewed to ensure the behavior is expected