Fix sub-man installation on EL8 (oamg#991)

Yumdownloader was downloading two different versions of the
subscription-manager-rhsm-certificates package and convert2rhel failed
when it wanted to install both at the same time.

subscription-manager-rhsm-certificates-1.28.36-3.el8_8.x86_64
subscription-manager-rhsm-certificates-20220623-1.el8.noarch

Pino Toscano from the subscription-manager team told us that the version
20220623 is the latest and the one we should be installing.

Since the two versions have different architecture, this quick solution
is making sure that only the noarch one is downloaded and installed.

convert2rhel/subscription.py

@@ -833,15 +833,15 @@ def _relevant_subscription_manager_pkgs():
             "python3-syspurpose",
             "python3-cloud-what",
             "json-c.x86_64",  # there's also an i686 version we don't need unless the json-c.i686 is already installed
-            "subscription-manager-rhsm-certificates",
+            "subscription-manager-rhsm-certificates.noarch",
         ]
 
     elif system_info.version.major >= 9:
         relevant_pkgs += [
             "libdnf-plugin-subscription-manager",
             "python3-subscription-manager-rhsm",
             "python3-cloud-what",
-            "subscription-manager-rhsm-certificates.x86_64",
+            "subscription-manager-rhsm-certificates.noarch",
         ]
 
     if system_info.is_rpm_installed("json-c.i686"):

convert2rhel/unit_tests/subscription_test.py

@@ -224,7 +224,7 @@ def test__dependencies_to_update_no_pkgs(self, monkeypatch, global_system_info):
                 frozenset(
                     (
                         "subscription-manager",
-                        "subscription-manager-rhsm-certificates",
+                        "subscription-manager-rhsm-certificates.noarch",
                         "python3-subscription-manager-rhsm",
                         "dnf-plugin-subscription-manager",
                         "python3-syspurpose",
@@ -239,7 +239,7 @@ def test__dependencies_to_update_no_pkgs(self, monkeypatch, global_system_info):
                 frozenset(
                     (
                         "subscription-manager",
-                        "subscription-manager-rhsm-certificates",
+                        "subscription-manager-rhsm-certificates.noarch",
                         "python3-subscription-manager-rhsm",
                         "dnf-plugin-subscription-manager",
                         "python3-syspurpose",
@@ -255,7 +255,7 @@ def test__dependencies_to_update_no_pkgs(self, monkeypatch, global_system_info):
                 frozenset(
                     (
                         "subscription-manager",
-                        "subscription-manager-rhsm-certificates.x86_64",
+                        "subscription-manager-rhsm-certificates.noarch",
                         "python3-subscription-manager-rhsm",
                         "python3-cloud-what",
                         "libdnf-plugin-subscription-manager",