fix(checker): Allow element access expressions in computed property names if argument is literal

[kairosci]

Fixes #25083.

This PR relaxes the check for computed property names in type literals (specifically in isLateBindableAST) to allow ElementAccessExpression when the argument is a static literal.

Changes

• Updated isLateBindableAST to use a new helper isLateBindableExpression.
• isLateBindableExpression recursively checks the expression and allows:
  • String literals (e.g., Enum['key'])
  • Numeric literals
  • Signed numeric literals (e.g., Enum[-1])
  • Parenthesized expressions (e.g., Enum[('key')])

Example

enum Type {
  '3x14' = '3x14'
}
enum Numeric {
    Negative = -1,
}

type TypeMap = {
  [Type['3x14']]: any;       // Now valid
  [Numeric['Negative']]: any; // Now valid
  [Numeric[('Negative')]]: any; // Now valid
}

Verified with new test case tests/cases/compiler/enumKeysInTypeLiteral.ts covering these scenarios.