LibWeb/IDB: Implement clear_an_object_store

Author: https://github.com/stelar7
Commit: https://github.com/LadybirdBrowser/ladybird/commit/637f35c0eb7
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4650
Reviewed-by: https://github.com/AtkinsSJ ✅

Libraries/LibWeb/IndexedDB/Internal/ObjectStore.h

@@ -55,6 +55,7 @@ public:
     void store_a_record(Record const& record);
     u64 count_records_in_range(GC::Ref<IDBKeyRange> range);
     Optional<Record&> first_in_range(GC::Ref<IDBKeyRange> range);
+    void clear_records();
 
 protected:
     virtual void visit_edges(Visitor&) override;