Fix junos integration test failure (#28491)

Pass ssh_config value to ncclient manager api as None
if it is not set.

lib/ansible/plugins/connection/netconf.py

@@ -25,6 +25,7 @@ import json
 from ansible import constants as C
 from ansible.errors import AnsibleConnectionFailure, AnsibleError
 from ansible.module_utils._text import to_bytes, to_native, to_text
+from ansible.module_utils.parsing.convert_bool import BOOLEANS_TRUE
 from ansible.plugins.loader import netconf_loader
 from ansible.plugins.connection import ConnectionBase, ensure_connect
 from ansible.utils.jsonrpc import Rpc
@@ -86,8 +87,10 @@ class Connection(Rpc, ConnectionBase):
             raise AnsibleConnectionFailure('Unable to automatically determine host network os. Please ansible_network_os value')
 
         ssh_config = os.getenv('ANSIBLE_NETCONF_SSH_CONFIG', False)
-        if ssh_config == 'True':
+        if ssh_config in BOOLEANS_TRUE:
             ssh_config = True
+        else:
+            ssh_config = None
 
         try:
             self._manager = manager.connect(