Desktop: Fixes #3628: Add scroll offset for dragging notes (#3651)

The note draging was not taking into account the scroll distance.
This caused the notes to be dragged to a different location than the mouse.
This scroll offset should fix that issue.

ElectronClient/gui/ItemList.jsx

@@ -36,6 +36,10 @@ class ItemList extends React.Component {
 		return this.listRef.current ? this.listRef.current.offsetTop : 0;
 	}
 
+	offsetScroll() {
+		return this.scrollTop_;
+	}
+
 	UNSAFE_componentWillMount() {
 		this.updateStateItemIndexes();
 	}

ElectronClient/gui/NoteList/NoteList.tsx

@@ -140,7 +140,7 @@ class NoteListComponent extends React.Component {
 	}
 
 	dragTargetNoteIndex_(event:any) {
-		return Math.abs(Math.round((event.clientY - this.itemListRef.current.offsetTop()) / this.itemHeight)) - 1;
+		return Math.abs(Math.round((event.clientY - this.itemListRef.current.offsetTop() + this.itemListRef.current.offsetScroll()) / this.itemHeight));
 	}
 
 	noteItem_noteDragOver(event:any) {