LibWeb: Add imports to all IDL files that depend on others

Author: https://github.com/alimpfard
Commit: a59800b4a0
Pull-request: https://github.com/SerenityOS/serenity/pull/12548
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibWeb/CSS/MediaList.idl

@@ -1,5 +1,5 @@
 interface MediaList {
-    stringifier attribute [LegacyNullToEmptyString] CSSOMString mediaText;
+    [LegacyNullToEmptyString] stringifier attribute CSSOMString mediaText;
     readonly attribute unsigned long length;
     getter CSSOMString? item(unsigned long index);
     undefined appendMedium(CSSOMString medium);