Fix authorized_key crash in Python3 with remote key file (ansible#20037)

* Decode downloaded keys bytes if Python3
* Fixes ansible#20007
* Thanks @georgepsarakis

lib/ansible/modules/system/authorized_key.py

@@ -227,6 +227,7 @@
 import shlex
 from operator import itemgetter
 
+from ansible.module_utils._text import to_native
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.pycompat24 import get_exception
 from ansible.module_utils.urls import fetch_url
@@ -537,6 +538,9 @@ def enforce_state(module, params):
         except Exception:
             module.fail_json(msg=error_msg % key)
 
+        # resp.read gives bytes on python3, convert to native string type
+        key = to_native(key, errors='surrogate_or_strict')
+
     # extract individual keys into an array, skipping blank lines and comments
     new_keys = [s for s in key.splitlines() if s and not s.startswith('#')]