fix: refer to portnumber property correctly

[lowlydba]

Description

Make sure we're comparing a property that is actually returned from the listener getter

How Has This Been Tested?

We don't have AG tests due to the complexity at this time.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue) - Fixes #206
• [ ] New feature (non-breaking change which adds functionality)

Checklist:

• [x] I have read/followed the CONTRIBUTING document.
• [x] I have read/followed the PR Quick Start Guide
• [x] I have added tests to cover my changes or they are N/A.
• [ ] I have added a changelog fragment describing the changes.
• [ ] New module options/parameters include a version_added property.

[codecov-commenter]

Codecov Report

All modified lines are covered by tests :white_check_mark:

Comparison is base (787f403) 93.68% compared to head (71631d4) 100.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #209 +/- ## =========================================== + Coverage 93.68% 100.00% +6.31% =========================================== Files 64 33 -31 Lines 2202 106 -2096 =========================================== - Hits 2063 106 -1957 + Misses 139 0 -139 ``` | [Flag](https://app.codecov.io/gh/lowlydba/lowlydba.sqlserver/pull/209/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=John+McCall) | Coverage Δ | | |---|---|---| | [sanity](https://app.codecov.io/gh/lowlydba/lowlydba.sqlserver/pull/209/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=John+McCall) | `100.00% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=John+McCall#carryforward-flags-in-the-pull-request-comment) to find out more. [see 31 files with indirect coverage changes](https://app.codecov.io/gh/lowlydba/lowlydba.sqlserver/pull/209/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=John+McCall)

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[github-actions[bot]]

Docs Build 📝

Thank you for contribution!✨

This PR has been merged and the docs are now incorporated into main: https://lowlydba.github.io/lowlydba.sqlserver/branch/main