Add unit tests for mycli/packages/special/utils.py

[rolandwalker]

Description

Add unit tests for mycli/packages/special/utils.py, migrating existing format_uptime() tests, and adding new tests, in a new file.

The changelog is covered in a general entry in a separate PR.

Motivation: greater test coverage makes the code more amenable to agentic coding.

Checklist

• I added this contribution to the changelog.md file.
• I added my name to the AUTHORS file (or it's already there).
• To lint and format the code, I ran

  uv run ruff check && uv run ruff format && uv run mypy --install-types .

[github-actions]

1. Medium - cd success path test can pass even if os.chdir() is never called
   In test_special_utils.py:36, os.chdir is replaced with a no-op lambda and never asserted. Because os.getcwd is also hardcoded, this test would still pass if handle_cd_command() stopped changing directories and only echoed CWD.
   Action: use a MagicMock for os.chdir and assert assert_called_once_with('/tmp/target').

2. Low - SSL error-path test does not verify cache/retry behavior
   In test_special_utils.py:173, the test checks only one failing call. It does not verify that an OperationalError is not cached and that a subsequent call retries SHOW STATUS LIKE "Ssl_version".
   Action: add a second call after clearing the side effect (or using side_effect sequence) and assert execute call count increments and result can recover.

No direct correctness/security regressions were found in production code in this PR (it only changes tests).

I could not execute the tests locally because uv is not available in this environment (uv: command not found).