Prevent NaN baselines in Paper nested Text layout

[Copilot]

Baseline-aligned nested View/Text layouts can terminate macOS Paper with Expect custom baseline function to not return NaN. Yoga’s measure-only pass can reach unmeasured descendant text, whose undefined height becomes CGFLOAT_MAX and converts back to NaN.

• Baseline calculation: Use TextKit’s measured text height when the supplied height is undefined. Preserve the existing baseline formula for finite heights and leave Yoga’s assertion intact.
• Regression coverage: Add native tests for undefined/non-finite dimensions, empty text, explicit heights, and nested baseline-aligned fixed-size views across repeated layouts.

• Fixes [Paper][0.81.9] Baseline-aligned nested Text layout aborts with ‘Expect custom baseline function to not return NaN’ #3121

[azure-pipelines]

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