Fix airflowctl crash when incorrect keyring password is entered

[dheerajturaga]

When using an encrypted keyring with airflowctl, entering an incorrect
keyring password caused an unhandled ValueError exception. This adds
proper exception handling in Credentials.load() to provide user-friendly
error messages with actionable steps for recovery. AUTH commands now
continue gracefully while CLI commands display helpful guidance.

Please enter password for encrypted keyring:
Please enter password for encrypted keyring:
Traceback (most recent call last):
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file.py", line 186, in _unlock
    ref_pw = self.get_password('keyring-setting', 'password reference')
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file_base.py", line 106, in get_password
    password = self.decrypt(password_encrypted, assoc).decode('utf-8')
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file.py", line 218, in decrypt
    assert plaintext.startswith(self.pw_prefix)
AssertionError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file_base.py", line 106, in get_password
    password = self.decrypt(password_encrypted, assoc).decode('utf-8')
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file.py", line 216, in decrypt
    cipher = self._create_cipher(self.keyring_key, data['salt'], data['IV'])
  File "/usr/python/lib/python3.10/site-packages/jaraco/classes/properties.py", line 76, in __get__
    return self.fget(obj)
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file.py", line 99, in keyring_key
    self._unlock()
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file.py", line 190, in _unlock
    raise ValueError("Incorrect Password")
ValueError: Incorrect Password

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file.py", line 186, in _unlock
    ref_pw = self.get_password('keyring-setting', 'password reference')
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file_base.py", line 106, in get_password
    password = self.decrypt(password_encrypted, assoc).decode('utf-8')
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file.py", line 218, in decrypt
    assert plaintext.startswith(self.pw_prefix)
AssertionError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/python/bin/airflowctl", line 10, in <module>
    sys.exit(main())
  File "/opt/airflow/airflow-ctl/src/airflowctl/__main__.py", line 34, in main
    safe_call_command(args.func, args=args)
  File "/opt/airflow/airflow-ctl/src/airflowctl/ctl/cli_config.py", line 76, in safe_call_command
    function(args)
  File "/opt/airflow/airflow-ctl/src/airflowctl/ctl/cli_config.py", line 59, in command
    return func(*args, **kwargs)
  File "/opt/airflow/airflow-ctl/src/airflowctl/api/client.py", line 355, in wrapper
    with get_client(kind=kind) as api_client:
  File "/usr/python/lib/python3.10/contextlib.py", line 135, in __enter__
    return next(self.gen)
  File "/opt/airflow/airflow-ctl/src/airflowctl/api/client.py", line 323, in get_client
    credentials = Credentials(client_kind=kind).load()
  File "/opt/airflow/airflow-ctl/src/airflowctl/api/client.py", line 172, in load
    self.api_token = keyring.get_password("airflowctl", f"api_token_{self.api_environment}")
  File "/usr/python/lib/python3.10/site-packages/keyring/core.py", line 63, in get_password
    return get_keyring().get_password(service_name, username)
  File "/usr/python/lib/python3.10/site-packages/keyring/backends/chainer.py", line 49, in get_password
    password = keyring.get_password(service, username)
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file_base.py", line 109, in get_password
    password = self.decrypt(password_encrypted).decode('utf-8')
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file.py", line 216, in decrypt
    cipher = self._create_cipher(self.keyring_key, data['salt'], data['IV'])
  File "/usr/python/lib/python3.10/site-packages/jaraco/classes/properties.py", line 76, in __get__
    return self.fget(obj)
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file.py", line 99, in keyring_key
    self._unlock()
  File "/usr/python/lib/python3.10/site-packages/keyrings/alt/file.py", line 190, in _unlock
    raise ValueError("Incorrect Password")
ValueError: Incorrect Password

[potiuk]

LGTM with one comment about communicating errors to the users which requires @bugraoz93 input.

[bugraoz93]

Nice! Thanks!