Fix refactoring in tooltips

[Tanya-Solyanik]

Introduced in https://github.com/dotnet/winforms/commit/ca1199eb6cfaf8ecd26ee429761764ea264dd2f5 -

Tooltip owner window is used for tooltip placement when tool is not a control, this is the case of ToolStripItems.

Microsoft Reviewers: Open in CodeFlow

[elachlan]

Test failure unrelated.

System.Windows.Forms.Tests.ClipboardTests.Clipboard_SetText_InvokeStringTextDataFormat_GetReturnsExpected(format: Text)

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 74.26649%. Comparing base (31176a4) to head (0433fde). Report is 5 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #11388 +/- ## =================================================== - Coverage 74.27181% 74.26649% -0.00532% =================================================== Files 3025 3025 Lines 626861 626852 -9 Branches 46742 46740 -2 =================================================== - Hits 465581 465541 -40 - Misses 157935 157958 +23 - Partials 3345 3353 +8 ``` | [Flag](https://app.codecov.io/gh/dotnet/winforms/pull/11388/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/11388/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `74.26649% <0.00000%> (-0.00532%)` | :arrow_down: | | [integration](https://app.codecov.io/gh/dotnet/winforms/pull/11388/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `17.98313% <0.00000%> (-0.01878%)` | :arrow_down: | | [production](https://app.codecov.io/gh/dotnet/winforms/pull/11388/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `46.98492% <0.00000%> (-0.01257%)` | :arrow_down: | | [test](https://app.codecov.io/gh/dotnet/winforms/pull/11388/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `96.99415% <ø> (ø)` | | | [unit](https://app.codecov.io/gh/dotnet/winforms/pull/11388/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `43.97002% <0.00000%> (+0.00208%)` | :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.