fix token check of image build repositories

[mcalmer]

What does this PR change?

Download Tokens of image build repositories are not stored in DB.
The valid check needs to pass if they are not found.

GUI diff

No difference.

• DONE

Documentation

• No documentation needed: only internal and user invisible changes

• DONE

Test coverage

• No tests: add explanation

• No tests: already covered

• Unit tests were added

• Cucumber tests were added

• DONE

Links

Port of https://github.com/SUSE/spacewalk/pull/22727

• DONE

Changelogs

Make sure the changelogs entries you are adding are compliant with https://github.com/uyuni-project/uyuni/wiki/Contributing#changelogs and https://github.com/uyuni-project/uyuni/wiki/Contributing#uyuni-projectuyuni-repository

If you don't need a changelog check, please mark this checkbox:

• No changelog needed

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Re-run a test

If you need to re-run a test, please mark the related checkbox, it will be unchecked automatically once it has re-run:

• Re-run test "changelog_test"
• Re-run test "backend_unittests_pgsql"
• Re-run test "java_pgsql_tests"
• Re-run test "schema_migration_test_pgsql"
• Re-run test "susemanager_unittests"
• Re-run test "javascript_lint"
• Re-run test "spacecmd_unittests"

[github-actions]

Suggested tests to cover this Pull Request

• minssh_salt_install_package
• srv_user_api
• min_deblike_monitoring
• min_salt_mgrcompat_state
• proxy_cobbler_pxeboot
• allcli_software_channels_dependencies
• allcli_system_group
• minkvm_guests
• srv_rename_hostname
• srv_docker_cve_audit
• srv_cobbler_profile
• min_ansible_control_node
• min_retracted_patches
• min_activationkey
• allcli_reboot
• min_bootstrap_ssh_key
• srv_manage_activationkey
• min_salt_formulas_advanced
• srv_manage_channels_page
• min_deblike_salt_install_package
• buildhost_docker_build_image
• min_recurring_action
• proxy_as_pod_basic_tests
• minssh_bootstrap_api
• srv_advanced_search
• min_salt_minion_details
• min_salt_lock_packages
• min_deblike_openscap_audit
• min_check_patches_install
• min_virthost
• min_salt_openscap_audit
• min_salt_install_with_staging
• min_move_from_and_to_proxy
• allcli_config_channel
• min_salt_software_states
• min_timezone
• min_bootstrap_api
• min_bootstrap_reactivation
• min_rhlike_monitoring
• min_salt_user_states
• minssh_ansible_control_node
• min_rhlike_salt_install_package_and_patch
• min_config_state_channel_api
• buildhost_docker_auth_registry
• buildhost_osimage_build_image
• srv_monitoring
• min_deblike_salt_install_with_staging
• min_cve_audit
• allcli_action_chain
• min_salt_pkgset_beacon
• proxy_retail_pxeboot_and_mass_import
• buildhost_bootstrap
• proxy_branch_network
• min_rhlike_openscap_audit
• min_bootstrap_script
• srv_salt_download_endpoint
• min_cve_id_new_syntax
• allcli_sanity
• min_deblike_ssh
• min_salt_install_package
• min_salt_minions_page
• min_monitoring
• min_change_software_channel
• min_action_chain
• minssh_action_chain
• sle_ssh_minion
• min_salt_formulas
• allcli_overview_systems_details
• min_custom_pkg_download_endpoint
• allcli_software_channels
• sle_minion
• min_ssh_tunnel
• minssh_move_from_and_to_proxy