Merge branch '5.4' into 6.0

* 5.4:
  [Tests] Remove some unused fixtures
  added missing translations for portuguese [#43726]
  [HttpClient][Mime] Add correct IDN flags for IDNA2008 compliance
  Prevent installation of incompatible mailer component versions
  properly parse quoted strings tagged with !!str
  do not merge label classes into expanded choice labels
  Bump Symfony version to 5.4.0
  Update VERSION for 5.4.0-BETA3
  Update CHANGELOG for 5.4.0-BETA3
  [Serializer] PropertyNormalizer - return unique (i.e. filter duplicate ) attributes in extractAttributes function
  Allow autodetecting mapping type for any object

Author: derrabus