fix(parser-jsx): skip text node conversion when expression contains JSX

[omairqazi29]

Summary

When a JSXExpressionContainer contains JSX elements (e.g., from .map() or conditional rendering), the parser now skips adding a {expression} text placeholder. This prevents false positives for elements like <dl> that don't allow text children.

Problem:
Previously, expressions like {items.map(item => <div>...</div>)} would generate both:

1. A {expression} text node
2. The nested JSX elements

This caused validation errors for elements like <dl>, <ul>, <ol> etc. that don't allow text children.

Solution:
Added a containsJSXElement() function that recursively checks if an expression contains JSX elements. When it does, we skip the text node conversion since the JSX elements will be processed separately.

Changes

• Added containsJSXElement() helper function to detect JSX elements within expressions
• Modified JSXExpressionContainer handler to skip text placeholder when expression contains JSX
• Added 4 new test cases covering the fix

Test plan

• All existing tests pass (22 tests)
• New test: It omits expression placeholder when expression contains JSX (dl with map)
• New test: It omits expression placeholder when expression contains JSX (conditional)
• New test: It omits expression placeholder in div when expression contains JSX
• New test: It keeps expression placeholder when expression does not contain JSX

Fix #4624

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: omairqazi29 / name: Qazi Omair Ahmed (bdd16b1)