Fix file sync error if local item version is greater than remote item

This can happen because objects are uploaded in batches, but the version
number from the last batch is used for all objects (since
APIClient.uploadObjects() handles batching internally).

chrome/content/zotero/xpcom/storage/zfs.js

@@ -495,10 +495,6 @@ Zotero.Sync.Storage.Mode.ZFS.prototype = {
 					syncRequired: true
 				});
 			}
-			if (version < item.version) {
-				throw new Error("Last-Modified-Version is lower than item version "
-					+ `(${version} < ${item.version})`);
-			}
 			
 			// Get updated item metadata
 			let library = Zotero.Libraries.get(item.libraryID);