LibWeb: Add stub for IDBFactory

Author: https://github.com/shannonbooth
Commit: 8d5665ebe1
Pull-request: https://github.com/SerenityOS/serenity/pull/24377
Reviewed-by: https://github.com/tcl3

Userland/Libraries/LibWeb/Forward.h

@@ -498,6 +498,10 @@ namespace Web::HighResolutionTime {
 class Performance;
 }
 
+namespace Web::IndexedDB {
+class IDBFactory;
+}
+
 namespace Web::Internals {
 class Inspector;
 class Internals;