Add test coverage for ListView

[MandiMan]

Related https://github.com/dotnet/winforms/issues/10453

Proposed changes

• Add unit tests for ListView to test its events: TextChanged, AfterLabelEdit, BeforeLabelEdit, CacheVirtualItems

  Microsoft Reviewers: Open in CodeFlow

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 74.27990%. Comparing base (74caf32) to head (dcab039). Report is 15 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #11380 +/- ## =================================================== + Coverage 74.26878% 74.27990% +0.01111% =================================================== Files 3025 3026 +1 Lines 626861 627027 +166 Branches 46742 46753 +11 =================================================== + Hits 465562 465755 +193 + Misses 157959 157919 -40 - Partials 3340 3353 +13 ``` | [Flag](https://app.codecov.io/gh/dotnet/winforms/pull/11380/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | Coverage Δ | | |---|---|---| | [Debug](https://app.codecov.io/gh/dotnet/winforms/pull/11380/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `74.27990% <100.00000%> (+0.01111%)` | :arrow_up: | | [integration](https://app.codecov.io/gh/dotnet/winforms/pull/11380/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `17.99171% <ø> (-0.01301%)` | :arrow_down: | | [production](https://app.codecov.io/gh/dotnet/winforms/pull/11380/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `47.00906% <ø> (+0.01824%)` | :arrow_up: | | [test](https://app.codecov.io/gh/dotnet/winforms/pull/11380/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `96.98831% <100.00000%> (-0.00585%)` | :arrow_down: | | [unit](https://app.codecov.io/gh/dotnet/winforms/pull/11380/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `43.98724% <ø> (+0.05160%)` | :arrow_up: | 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=dotnet#carryforward-flags-in-the-pull-request-comment) to find out more.