[Validator] Added missing strings from Image validator
[Validator] Add missing polish translations
Merge branch '2.4'

* 2.4:
  Update MimeTypeExtensionGuesser.php
  [Validator] Add missing polish translations
  [Validator] Added missing strings from Image validator
  [Templating] PhpEngine should propagate charset to its helpers
  Fix ticket #10663 - Added setCharset method call to PHP templating engine.
  Changed the typehint of the EsiFragmentRenderer to the interface
  [Form] Improved test coverage of UrlType
  [BrowserKit] Fix #10641 : BrowserKit is broken when using ip as host