Group / ungroup should not always be present in the context menu (#1890)

Co-authored-by: rene_mbp <harryloveslearning@googlemail.com>
Co-authored-by: dwelle <luzar.david@gmail.com>

src/actions/types.ts

@@ -81,6 +81,10 @@ export interface Action {
   ) => boolean;
   contextItemLabel?: string;
   contextMenuOrder?: number;
+  contextItemPredicate?: (
+    elements: readonly ExcalidrawElement[],
+    appState: AppState,
+  ) => boolean;
 }
 
 export interface ActionsManagerInterface {