Merge branch '6.4' into 7.0

* 6.4:
  [Form] Fix merging form data and files (ter)
  [Intl] Update the ICU data to 74.1
  [Scheduler] Use MockClock
  [AssetMapper] Fixing memory bug where we stored way more file content than needed
  [AssetMapper] jsdelivr "no version" import syntax
  [HtmlSanitizer] Consider `width` attribute as safe
  [DoctrineBridge] Fix exception message
  [Security][Validator] Missing translations for Luxembourgish

Resources/data/parents.json

@@ -35,6 +35,7 @@
     "en_GM": "en_001",
     "en_GY": "en_001",
     "en_HK": "en_001",
+    "en_ID": "en_001",
     "en_IE": "en_001",
     "en_IL": "en_001",
     "en_IM": "en_001",