CLOS-4056 follow-up: gate check_cl_license on is_cln_package_channel_active() + fix dead inhibitor branch

The check_cl_license actor verifies CL licensing by calling /usr/sbin/rhn_check,
which under rhn-client-tools >= 3.0 does an XML-RPC roundtrip to CLN to refresh
the JWT credential. On a no-auth (SWNG) system the systemid file written by
clnreg_ks (2.x flow) is not in the format rhn_check 3.0+ expects against the
prod CLN server, and the call dies with

    rhn-plugin: Error communicating with server. The message was:
    com.cloudlinux.clos.domain.exceptions.xmlrpc.ClnXmlRpcException:
    (=_=) Invalid System Credentials. Cannot parse request or identify
    server. Please, run registration again.

elevate-qa Run #55 hit this immediately after the CLBS bundle began landing
rhn-client-tools 3.0.3 source-side (now that the cln-switch-channel=2 install-
time pin no longer forces a 2.x downgrade).

Under no-auth, licensing is not the CLN XML-RPC roundtrip - it's IP-based
(or other static mechanisms). The rhn_check route is the wrong validation
here. Gate the actor on is_cln_package_channel_active() and skip when it
returns False, matching the same pattern the other CLOS-4056-gated actors
use (switchclnchannel, pinclnmirror, copycllicense, ...).

While here, fix a pre-existing dead-code bug: `run([rhn_check_bin])` raises
CalledProcessError on non-zero exit, so the `if not res or res['exit_code']
!= 0 or res['stderr']: produce inhibitor` branch never executed on CLN-active
failures - the actor crashed instead of producing the intended INHIBITOR
report. Wrap the run() call in try/except so the existing reporting path
takes over when rhn_check fails on a CLN-active system.

Author: prilr

repos/system_upgrade/cloudlinux/actors/checkcllicense/actor.py

@@ -4,6 +4,7 @@
 from leapp.tags import ChecksPhaseTag, IPUWorkflowTag
 from leapp.libraries.stdlib import CalledProcessError, run, api
 from leapp.libraries.common.cllaunch import run_on_cloudlinux
+from leapp.libraries.common.cln_detect import is_cln_package_channel_active
 
 from leapp.models import (
     TargetUserSpacePreupgradeTasks,
@@ -29,10 +30,34 @@ class CheckClLicense(Actor):
 
     @run_on_cloudlinux
     def process(self):
+        # CLOS-4056: the rhn_check XML-RPC call only verifies licenses on
+        # systems that use CLN as the package channel. Under no-auth (SWNG)
+        # the license is conveyed by other means (IP-based licensing,
+        # cloudlinux-release content) and the rhn_check round-trip is not a
+        # meaningful gate - on rhn-client-tools 3.0+ it fails outright with
+        # "Invalid System Credentials" against systemid files written by
+        # clnreg_ks. Skip the check under no-auth.
+        if not is_cln_package_channel_active():
+            api.current_logger().info(
+                "CLN is not the active package channel; skipping rhn_check"
+                " license verification (no-auth systems use IP licensing,"
+                " not the CLN XML-RPC roundtrip)."
+            )
+            return
+
         res = None
         if os.path.exists(self.system_id_path):
-            res = run([self.rhn_check_bin])
-            self.log.debug('rhn_check result: %s', res)
+            try:
+                res = run([self.rhn_check_bin])
+                self.log.debug('rhn_check result: %s', res)
+            except CalledProcessError as e:
+                # The original implementation assigned `res = run(...)`
+                # bare, but `run()` raises on non-zero exit codes - so
+                # the "produce an inhibitor on non-zero / non-empty stderr"
+                # branch below was dead code. Catch the failure and let
+                # the existing reporting path take over.
+                self.log.debug('rhn_check failed: %s', e)
+                res = None
         if not res or res['exit_code'] != 0 or res['stderr']:
             title = 'Server does not have an active CloudLinux license'
             summary = 'Server does not have an active CloudLinux license. This renders key CloudLinux packages ' \