…RL isn’t empty

* 6.4:
  Fix Warning: curl_multi_select(): timeout must be positive
  [PropertyInfo] Fix ReflectionExtractor handling of underscore-only property names
  ObjectNormalizer: allow null and scalar
  [Security] Fix `HttpUtils::createRequest()` when the context’s base URL isn’t empty
  [Serializer] fix Inherited properties normalization
  [OptionsResolver] Fix missing prototype key in nested error paths
  Bump Symfony version to 6.4.30
  Update VERSION for 6.4.29
  Update CHANGELOG for 6.4.29
  [Yaml] Fix parsing of unquoted multiline scalars with comments or blank lines
  [Clock] Align MockClock::sleep() behavior with NativeClock for negative values
  [OptionsResolver] Ensure remove() also unsets deprecation status
  Remove review state for Belarusian translations (entries 141 and 142)
  [ExpressionLanguage] Compile numbers with var_export in Compiler::repr for thread-safety
  compatibility with ext-redis 6.3
  [Serializer] Fix BackedEnumNormalizer behavior with partial denormalization