Fix: unbounded layout errors

[ss0314]

Summary

This PR fixes critical unbounded layout errors that occur when using complex math widgets like \sqrt, and \left...\right inside layouts with unbounded vertical constraints, such as Column, ListView, or SingleChildScrollView.

The Problem

When a Math widget is placed in a vertically unbounded container, several internal components fail:

1. RenderLine: Passes an infiniteConstraint to its children during the initial layout phase.
2. FracNode & LeftRightNode: Their layout delegates (FracLayoutDelegate, LeftRightNode's buildWidget) are not designed to handle infinite height constraints passed from RenderLine. They attempt calculations with Infinity or null values, leading to exceptions like:
   • _RenderLayoutBuilderPreserveBaseline object was given an infinite size during layout.
   • Type errors during layout calculations.

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✅ ss0314
❌ dakshatsuraasa
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