fix(files_trashbin): Only remove element if loaded

Make sure to only remove elements from file list (while restoring)
if the element was added to the file list (might not be added, if the list is scrolling).

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

Author: susnux

apps/files_trashbin/src/filelist.js

@@ -168,7 +168,10 @@
 				var $el
 				for (var i = 0; i < files.length; i++) {
 					$el = this.remove(OC.basename(files[i]), { updateSummary: false })
-					this.fileSummary.remove({ type: $el.attr('data-type'), size: $el.attr('data-size') })
+					// Only remove element if already loaded (might be unloaded if scrollable list)
+					if ($el) {
+						this.fileSummary.remove({ type: $el.attr('data-type'), size: $el.attr('data-size') })
+					}
 				}
 				this.fileSummary.update()
 				this.updateEmptyContent()