create or get active instance for show terminal accessibility help (#…

…172845)

fix #172195

src/vs/workbench/contrib/terminal/browser/terminalService.ts

@@ -529,7 +529,10 @@ export class TerminalService implements ITerminalService {
 	}
 
 	showTerminalAccessibilityHelp(): void {
-		this.activeInstance?.showAccessibilityHelp();
+		this.getActiveOrCreateInstance().then((instance) => {
+			this._terminalGroupService.showPanel();
+			instance.showAccessibilityHelp();
+		});
 	}
 
 	requestStartExtensionTerminal(proxy: ITerminalProcessExtHostProxy, cols: number, rows: number): Promise<ITerminalLaunchError | undefined> {