Show correct context menu and itemPane header for collections in trash (#4297)

- only have enabled "Permanently delete" and "Restore to library"
options in the context menu for collections and searches in the trash
- display the custom header with buttons to delete or restore
in the itemPane when a collection or search in the trash is selected

Fixes: #4295

chrome/content/zotero/elements/itemPane.js

@@ -492,7 +492,9 @@
 		getCurrentPane(mode = undefined) {
 			if (!mode) {
 				// Guess a mode from the current data
-				if (!this.data.length || this.data.length > 1) {
+				// No/multiple objects are selected OR selected object is a trashed collection/search
+				if (!this.data.length || this.data.length > 1
+					|| this.data[0] instanceof Zotero.Collection || this.data[0] instanceof Zotero.Search) {
 					mode = "message";
 				}
 				else if (this.data[0].isNote()) {

chrome/content/zotero/zoteroPane.js

@@ -3558,7 +3558,7 @@ var ZoteroPane = new function()
 			show.add(m.loadReport);
 		}
 		
-		var items = this.getSelectedItems();
+		var items = this.getSelectedObjects();
 		
 		if (items.length > 0) {
 			// Multiple items selected