Update PropertyRegistry to support clip-rule property

[jwmcglynn]

This pull request introduces support for the clip-rule property in the PropertyRegistry class, enhancing the SVG properties handling capabilities of the project.

• Adds parsing support for the clip-rule property in PropertyRegistry.cc. This includes the implementation of the ParseClipRule function to correctly parse the clip-rule values and update the property registry accordingly.
• Declares the clip-rule property in PropertyRegistry.h with appropriate cascading behavior set to Inherit. This ensures that the clip-rule property can be inherited as per SVG specifications.
• Updates the property map to include the clip-rule property, allowing it to be recognized and parsed within the SVG context.

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[codecov[bot]]

Codecov Report

Attention: Patch coverage is 77.21519% with 18 lines in your changes missing coverage. Please review.

Project coverage is 89.13%. Comparing base (3c12464) to head (49a4bc3). Report is 1 commits behind head on main.

Files	Patch %	Lines
donner/svg/properties/PropertyRegistry.cc	59.25%	7 Missing and 4 partials :warning:
donner/svg/core/ClipRule.h	0.00%	5 Missing :warning:
donner/svg/components/layout/LayoutSystem.cc	97.05%	0 Missing and 1 partial :warning:
donner/svg/renderer/RendererSkia.cc	90.90%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #171 +/- ## ========================================== - Coverage 89.38% 89.13% -0.25% ========================================== Files 254 255 +1 Lines 20276 20312 +36 Branches 2109 2119 +10 ========================================== - Hits 18123 18105 -18 - Misses 1561 1580 +19 - Partials 592 627 +35 ``` | [Flag](https://app.codecov.io/gh/jwmcglynn/donner/pull/171/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jeff+McGlynn) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/jwmcglynn/donner/pull/171/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jeff+McGlynn) | `89.13% <77.21%> (-0.12%)` | :arrow_down: | 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=Jeff+McGlynn#carryforward-flags-in-the-pull-request-comment) to find out more.

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